3 Monitor Setup, Primary Monitor sometimes deactivates

Hello, I am fairly new to Linux and Manjaro. I am running my current System since May.

Since the beginning I had this problem that sometimes for a seocnd or so my Primary Monitor goes black and comes back.

Today the problem was different. After booting everything was normal. but after a couple of minutes suddenly the Primary Monitor went black and stayed black and the other two monitors started to go crazy and then the system froze. first time that happen.

The first thing I did was revert from kernel 5.8.x back to kernel 5.7 as I switched a couple days ago. Everything was fine until suddenly my Primary Display again went black and stayed that way. I fixed it this time with disconnecting the Displayport cable from the grafics card and reconnected it, that fixed the problem for now.

inxi Ouput:

 inxi -Fxxxza --no-host
System:    Kernel: 5.7.17-2-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.0 
           parameters: BOOT_IMAGE=/boot/vmlinuz-5.7-x86_64 root=UUID=56b17ecb-f85b-4731-8854-f5a12b04d11f rw quiet apparmor=1 
           security=apparmor udev.log_priority=3 
           Desktop: KDE Plasma 5.19.4 tk: Qt 5.15.0 wm: kwin_x11 dm: SDDM Distro: Manjaro Linux 
Machine:   Type: Desktop Mobo: ASUSTeK model: PRIME X570-P v: Rev X.0x serial: <filter> UEFI: American Megatrends v: 1201 
           date: 09/09/2019 
CPU:       Topology: 6-Core model: AMD Ryzen 5 3600X bits: 64 type: MT MCP arch: Zen 2 family: 17 (23) model-id: 71 (113) 
           stepping: N/A microcode: 8701013 L2 cache: 3072 KiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm bogomips: 91067 
           Speed: 4039 MHz min/max: 2200/3800 MHz boost: enabled Core speeds (MHz): 1: 4253 2: 2459 3: 4233 4: 2134 5: 4264 
           6: 2127 7: 4203 8: 2138 9: 4284 10: 2463 11: 4210 12: 2144 
           Vulnerabilities: Type: itlb_multihit status: Not affected 
           Type: l1tf status: Not affected 
           Type: mds status: Not affected 
           Type: meltdown status: Not affected 
           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 AMD retpoline, IBPB: conditional, STIBP: always-on, RSB filling 
           Type: srbds status: Not affected 
           Type: tsx_async_abort status: Not affected 
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Navi 10 [Radeon RX 5600 OEM/5600 XT / 5700/5700 XT] vendor: XFX Pine 
           driver: amdgpu v: kernel bus ID: 0a:00.0 chip ID: 1002:731f 
           Display: x11 server: X.Org 1.20.8 compositor: kwin_x11 driver: amdgpu FAILED: ati unloaded: modesetting,radeon 
           alternate: fbdev,vesa display ID: :0 screens: 1 
           Screen-1: 0 s-res: 6400x1440 s-dpi: 96 s-size: 1693x381mm (66.7x15.0") s-diag: 1735mm (68.3") 
           Monitor-1: DisplayPort-0 res: 2560x1440 dpi: 93 size: 697x392mm (27.4x15.4") diag: 800mm (31.5") 
           Monitor-2: DisplayPort-1 res: 1920x1200 hz: 60 dpi: 94 size: 520x330mm (20.5x13.0") diag: 616mm (24.2") 
           Monitor-3: DisplayPort-2 res: 1920x1200 hz: 60 dpi: 94 size: 520x330mm (20.5x13.0") diag: 616mm (24.2") 
           OpenGL: renderer: AMD Radeon RX 5700 XT (NAVI10 DRM 3.37.0 5.7.17-2-MANJARO LLVM 10.0.1) v: 4.6 Mesa 20.1.6 
           direct render: Yes 
Audio:     Device-1: Advanced Micro Devices [AMD/ATI] Navi 10 HDMI Audio driver: snd_hda_intel v: kernel bus ID: 0a:00.1 
           chip ID: 1002:ab38 
           Device-2: Advanced Micro Devices [AMD] Starship/Matisse HD Audio vendor: ASUSTeK driver: snd_hda_intel v: kernel 
           bus ID: 0c:00.4 chip ID: 1022:1487 
           Sound Server: ALSA v: k5.7.17-2-MANJARO 
Network:   Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: ASUSTeK driver: r8169 v: kernel port: f000 
           bus ID: 04:00.0 chip ID: 10ec:8168 
           IF: enp4s0 state: up speed: 100 Mbps duplex: full mac: <filter> 
Drives:    Local Storage: total: 1.14 TiB used: 171.63 GiB (14.7%) 
           SMART Message: Unable to run smartctl. Root privileges required. 
           ID-1: /dev/nvme0n1 vendor: Samsung model: SSD 970 EVO Plus 250GB size: 232.89 GiB block size: physical: 512 B 
           logical: 512 B speed: 31.6 Gb/s lanes: 4 serial: <filter> rev: 2B2QEXM7 scheme: GPT 
           ID-2: /dev/sda vendor: Samsung model: SSD 860 QVO 1TB size: 931.51 GiB block size: physical: 512 B logical: 512 B 
           speed: 6.0 Gb/s serial: <filter> rev: 2B6Q scheme: GPT 
Partition: ID-1: / raw size: 232.59 GiB size: 227.94 GiB (98.00%) used: 50.24 GiB (22.0%) fs: ext4 dev: /dev/nvme0n1p2 
Swap:      Alert: No Swap data was found. 
Sensors:   System Temperatures: cpu: 58.9 C mobo: N/A gpu: amdgpu temp: 60 C 
           Fan Speeds (RPM): N/A gpu: amdgpu fan: 819 
Info:      Processes: 294 Uptime: 1h 32m Memory: 31.34 GiB used: 7.62 GiB (24.3%) Init: systemd v: 246 Compilers: gcc: 10.2.0 
           Packages: 1516 pacman: 1505 lib: 436 flatpak: 11 Shell: Bash v: 5.0.18 running in: konsole inxi: 3.1.05

Edit: it happened just now again. it seems that the grafics card stops sending a signal to the Monitor. after a few seconds I get the Message from the monitor no signal detected and going to stand by in a few seconds etc. just like before unplugging and reconnecting the displayport cable fixes the problem.

I’m having a similar issue. Manjaro KDE Kernel 5.12.9 as well as 5.10.42.
I’m using a docked Thinkpad T450s and a Samsung 4k monitor (U28E590). When turning the monitor on it keeps turning off after just a few seconds. It doesn’t matter if I extend the desktop or use only the external monitor. Happens on any HDMI or DP connector. I’m pretty sure it’s not the monitor because other devices work fine. Also if I’m switching to another TTY (text only) the monitor turns on and stays on. Same if I keep spaming the “extend to right” button that appears when pressing super + p. It’s like KDE forgets to send a “keep alive” signal or something (Is this a thing?).

Does anyone know what I can do about this?

Thanks in advance.