Monitor backlight off after suspend

Hi, I recently installed Manjaro and have been loving it. Unfortunately, I have been experiencing the problem that the monitor backlight of my laptop is completely deactivated after a suspend and I am forced to reboot. Thank you in advance for any tips!

What happens if you press CTRL+ALT+F2 and then CTRL+ALT+F1?

Nothing happens, unfortunately. I can, however, faintly see the login box and CTRL+ALT+DEL works. When I connect an external monitor, then I am able to log back in, but the laptop screen is still black. I have included some information below:

[holden@holden-20h1004tus ~]$ inxi -Fazy
  Kernel: 5.9.11-3-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.0 
  parameters: BOOT_IMAGE=/boot/vmlinuz-5.9-x86_64 
  root=UUID=5976b650-7fe7-4c78-83aa-f6d5d2569953 rw quiet apparmor=1 
  security=apparmor resume=UUID=8c366820-5313-4522-a7f0-1beec511d9b6 
  Desktop: Xfce 4.14.3 tk: Gtk 3.24.23 info: xfce4-panel wm: xfwm4 
  dm: LightDM 1.30.0 Distro: Manjaro Linux 
  Type: Laptop System: LENOVO product: 20H1004TUS v: ThinkPad E470 
  serial: <filter> Chassis: type: 10 serial: <filter> 
  Mobo: LENOVO model: 20H1004TUS v: SDK0J40697 WIN serial: <filter> 
  UEFI [Legacy]: LENOVO v: R0DET81W (1.81 ) date: 04/27/2017 
  ID-1: BAT0 charge: 34.0 Wh condition: 34.2/45.0 Wh (76%) volts: 12.3/11.1 
  model: LGC 01AV412 type: Li-poly serial: <filter> status: Not charging 
  Info: Dual Core model: Intel Core i7-7500U bits: 64 type: MT MCP 
  arch: Amber Lake family: 6 model-id: 8E (142) stepping: 9 microcode: DE 
  L2 cache: 4096 KiB 
  flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx 
  bogomips: 23209 
  Speed: 700 MHz min/max: 400/3500 MHz Core speeds (MHz): 1: 700 2: 700 3: 700 
  4: 700 
  Vulnerabilities: Type: itlb_multihit status: KVM: VMX disabled 
  Type: l1tf 
  mitigation: PTE Inversion; VMX: conditional cache flushes, SMT vulnerable 
  Type: mds mitigation: Clear CPU buffers; SMT vulnerable 
  Type: meltdown mitigation: PTI 
  Type: spec_store_bypass 
  mitigation: Speculative Store Bypass disabled via prctl and seccomp 
  Type: spectre_v1 
  mitigation: usercopy/swapgs barriers and __user pointer sanitization 
  Type: spectre_v2 mitigation: Full generic retpoline, IBPB: conditional, 
  IBRS_FW, STIBP: conditional, RSB filling 
  Type: srbds mitigation: Microcode 
  Type: tsx_async_abort status: Not affected 
  Device-1: Intel HD Graphics 620 vendor: Lenovo driver: i915 v: kernel 
  bus ID: 00:02.0 chip ID: 8086:5916 
  Device-2: NVIDIA GM108M [GeForce 940MX] vendor: Lenovo driver: nvidia 
  v: 455.45.01 alternate: nouveau,nvidia_drm bus ID: 01:00.0 
  chip ID: 10de:134d 
  Device-3: Realtek Integrated Camera type: USB driver: uvcvideo bus ID: 1-7:5 
  chip ID: 0bda:58db serial: <filter> 
  Display: x11 server: X.Org 1.20.10 driver: modesetting,nvidia 
  alternate: fbdev,intel,nouveau,nv,vesa display ID: :0.0 screens: 1 
  Screen-1: 0 s-res: 3840x1104 s-dpi: 96 s-size: 1016x292mm (40.0x11.5") 
  s-diag: 1057mm (41.6") 
  Monitor-1: eDP-1 res: 1920x1080 hz: 60 dpi: 158 size: 309x174mm (12.2x6.9") 
  diag: 355mm (14") 
  Monitor-2: HDMI-1 res: 1920x1080 hz: 60 dpi: 93 size: 527x296mm (20.7x11.7") 
  diag: 604mm (23.8") 
  OpenGL: renderer: Mesa Intel HD Graphics 620 (KBL GT2) v: 4.6 Mesa 20.2.3 
  direct render: Yes 
  Device-1: Intel Sunrise Point-LP HD Audio vendor: Lenovo 
  driver: snd_hda_intel v: kernel alternate: snd_soc_skl bus ID: 00:1f.3 
  chip ID: 8086:9d71 
  Sound Server: ALSA v: k5.9.11-3-MANJARO 
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet 
  vendor: Lenovo driver: r8169 v: kernel port: c000 bus ID: 04:00.0 
  chip ID: 10ec:8168 
  IF: enp4s0 state: down mac: <filter> 
  Device-2: Intel Wireless 8265 / 8275 driver: iwlwifi v: kernel port: c000 
  bus ID: 05:00.0 chip ID: 8086:24fd 
  IF: wlp5s0 state: up mac: <filter> 
  Local Storage: total: 238.47 GiB used: 9.90 GiB (4.2%) 
  SMART Message: Required tool smartctl not installed. Check --recommends 
  ID-1: /dev/sda vendor: SanDisk model: SD8TB8U256G1001 size: 238.47 GiB 
  block size: physical: 512 B logical: 512 B speed: 6.0 Gb/s serial: <filter> 
  rev: 3101 scheme: MBR 
  ID-1: / raw size: 229.67 GiB size: 225.06 GiB (97.99%) used: 9.90 GiB (4.4%) 
  fs: ext4 dev: /dev/sda1 
  Kernel: swappiness: 60 (default) cache pressure: 100 (default) 
  ID-1: swap-1 type: partition size: 8.80 GiB used: 0 KiB (0.0%) priority: -2 
  dev: /dev/sda2 
  System Temperatures: cpu: 46.0 C mobo: 0.0 C 
  Fan Speeds (RPM): cpu: 0 
  Processes: 243 Uptime: 7m Memory: 7.24 GiB used: 1.03 GiB (14.2%) 
  Init: systemd v: 246 Compilers: gcc: 10.2.0 Packages: pacman: 1087 lib: 325 
  flatpak: 0 Shell: Bash v: 5.0.18 running in: xfce4-terminal inxi: 3.1.08 
[holden@holden-20h1004tus ~]$ sudo dmesg -l emerg,alert,crit,err,warn
[    0.123176] MDS CPU bug present and SMT on, data leak possible. See for more details.
[    0.123176]  #3
[    0.126689] ENERGY_PERF_BIAS: Set to 'normal', was 'performance'
[    0.740202] ata1.00: supports DRM functions and may not be fully accessible
[    0.747433] ata1.00: supports DRM functions and may not be fully accessible
[    1.048905] usb: port power management may be unreliable
[    1.876770] nvidia: loading out-of-tree module taints kernel.
[    1.876783] nvidia: module license 'NVIDIA' taints kernel.
[    1.876783] Disabling lock debugging due to kernel taint
[    2.135706] NVRM: loading NVIDIA UNIX x86_64 Kernel Module  455.45.01  Thu Nov  5 23:03:56 UTC 2020
[    2.625966] acpi PNP0C14:01: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910 (first instance was on PNP0C14:00)
[    2.626091] acpi PNP0C14:02: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910 (first instance was on PNP0C14:00)
[    3.233608] r8169 0000:04:00.0: can't disable ASPM; OS doesn't have ASPM control
[    3.599238] thermal thermal_zone2: failed to read out thermal zone (-61)
[    6.217586] ACPI Warning: \_SB.PCI0.RP01.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20200717/nsarguments-59)
[    7.787955] kauditd_printk_skb: 45 callbacks suppressed
[   14.019569] kauditd_printk_skb: 2 callbacks suppressed
[  194.001659] kauditd_printk_skb: 19 callbacks suppressed
[  242.078897] smpboot: Scheduler frequency invariance went wobbly, disabling!
[  242.339987] iwlwifi 0000:05:00.0: RF_KILL bit toggled to enable radio.
[  242.653536] ata1.00: supports DRM functions and may not be fully accessible
[  242.659222] ata1.00: supports DRM functions and may not be fully accessible
[  252.956231] kauditd_printk_skb: 2 callbacks suppressed
[holden@holden-20h1004tus ~]$ sudo systemd-analyze blame
1.355s tlp.service                                                              
1.190s apparmor.service                                                         
1.169s lvm2-monitor.service                                                     
1.073s dev-sda1.device                                                          
 835ms systemd-random-seed.service                                              
 662ms systemd-modules-load.service                                             
 646ms systemd-udevd.service                                                    
 623ms snapd.service                                                            
 497ms systemd-logind.service                                                   
 478ms systemd-journald.service                                                 
 432ms upower.service                                                           
 237ms polkit.service                                                           
 185ms systemd-backlight@backlight:intel_backlight.service                      
 120ms systemd-journal-flush.service                                            
 110ms systemd-udev-trigger.service                                             
 106ms avahi-daemon.service                                                     
 101ms udisks2.service                                                          
 100ms NetworkManager.service                                                   
  95ms user@1000.service                                                        
  92ms systemd-rfkill.service                                                   
  81ms systemd-tmpfiles-clean.service                                           
  71ms lightdm.service                                                          
  52ms ModemManager.service                                                     
  37ms wpa_supplicant.service                                                   
  32ms systemd-tmpfiles-setup.service                                           
  32ms dev-disk-by\x2duuid-8c366820\x2d5313\x2d4522\x2da7f0\x2d1beec511d9b6.swap
  30ms systemd-tmpfiles-setup-dev.service                                       
  30ms accounts-daemon.service                                                  
  27ms snapd.apparmor.service                                                   
  24ms colord.service                                                           
  22ms bluetooth.service                                                        
  21ms linux-module-cleanup.service                                             
  21ms ufw.service                                                              
  18ms systemd-sysctl.service                                                   
  17ms systemd-user-sessions.service                                            
  13ms dev-hugepages.mount                                                      
  12ms user-runtime-dir@1000.service                                            
  12ms dev-mqueue.mount                                                         
  12ms systemd-remount-fs.service                                               
  11ms sys-kernel-debug.mount                                                   
  11ms systemd-update-utmp.service                                              
  10ms sys-kernel-tracing.mount                                                 
   9ms kmod-static-nodes.service                                                
   8ms modprobe@drm.service                                                     
   6ms rtkit-daemon.service                                                     
   4ms sys-fs-fuse-connections.mount                                            
   3ms snapd.socket                                                             
   2ms tmp.mount                                                                
   2ms sys-kernel-config.mount 

There seems to be an error here, but I am not sure if it is related:

[holden@holden-20h1004tus ~]$ sudo bootctl
Couldn't find EFI system partition. It is recommended to mount it to /boot or /efi.
Alternatively, use --esp-path= to specify path to mount point.
    Not booted with EFI

Have you tried kernel 5.4?