xrand shows ep1 (laptop screen), and dp1 and dp2 as disconnected. It also shows hdmi1 and hdmi2 separately and disconnected.
My laptop uses a USB-C Thunderbolt connection to provide the external hdmi interface. The laptop is capable of driving 2 external monitors plus laptop screen.
I have 2 USB-C devices plugged in, both have an HDMI. One by Aerofara also has VGA, ethernet and 3 USB3.0, plus analog audio and an SD card slot. The other dongle by Asus that came with machine has a USB-C, USB3 and HDMI.
Next thing I can think of to try is reboot into BIOS and see if there are any setting there that might cause these external HDMI ports to not show up under the OS.
Here are the system details from inxi:
System: Kernel: 5.8.6-1-MANJARO x86_64 bits: 64 compiler: N/A
parameters: BOOT_IMAGE=/boot/vmlinuz-5.8-x86_64 root=UUID=db854aac-7229-47ea-a7f7-3759e8d8ecf5 rw quiet
cryptdevice=UUID=090603d0-d1e0-4d7b-8f76-beca97122ab2:luks-090603d0-d1e0-4d7b-8f76-beca97122ab2
root=/dev/mapper/luks-090603d0-d1e0-4d7b-8f76-beca97122ab2 apparmor=1 security=apparmor
resume=/dev/mapper/luks-a14c2250-047f-4a75-b878-dadced3ad126 udev.log_priority=3
Desktop: KDE Plasma 5.19.5 tk: Qt 5.15.0 wm: kwin_x11 dm: SDDM Distro: Manjaro Linux
Machine: Type: Laptop System: ASUSTeK product: UX490UAR v: 1.0 serial: <filter>
Mobo: ASUSTeK model: UX490UAR v: 1.0 serial: <filter> UEFI: American Megatrends v: UX490UAR.307 date: 04/17/2019
Battery: ID-1: BAT0 charge: 37.4 Wh condition: 37.8/46.2 Wh (82%) volts: 7.7/7.7 model: ASUSTeK ASUS Battery type: Li-ion
serial: N/A status: Not charging cycles: 30
Memory: RAM: total: 15.50 GiB used: 2.15 GiB (13.9%)
RAM Report: permissions: Unable to run dmidecode. Root privileges required.
CPU: Topology: Quad Core model: Intel Core i7-8550U bits: 64 type: MT MCP arch: Kaby Lake family: 6 model-id: 8E (142)
stepping: A (10) microcode: D6 L2 cache: 8192 KiB bogomips: 32012
Speed: 700 MHz min/max: 400/4000 MHz Core speeds (MHz): 1: 700 2: 700 3: 701 4: 700 5: 700 6: 700 7: 700 8: 700
Flags: 3dnowprefetch abm acpi adx aes aperfmperf apic arat arch_perfmon art avx avx2 bmi1 bmi2 bts clflush
clflushopt cmov constant_tsc cpuid cpuid_fault cx16 cx8 de ds_cpl dtes64 dtherm dts epb ept ept_ad erms est f16c
flexpriority flush_l1d fma fpu fsgsbase fxsr ht hwp hwp_act_window hwp_epp hwp_notify ibpb ibrs ida intel_pt
invpcid invpcid_single lahf_lm lm mca mce md_clear mmx monitor movbe mpx msr mtrr nonstop_tsc nopl nx pae pat pbe
pcid pclmulqdq pdcm pdpe1gb pebs pge pln pni popcnt pse pse36 pti pts rdrand rdseed rdtscp rep_good sdbg sep smap
smep ss ssbd sse sse2 sse4_1 sse4_2 ssse3 stibp syscall tm tm2 tpr_shadow tsc tsc_adjust tsc_deadline_timer vme vmx
vnmi vpid x2apic xgetbv1 xsave xsavec xsaveopt xsaves xtopology xtpr
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
Graphics: Device-1: Intel UHD Graphics 620 vendor: ASUSTeK driver: i915 v: kernel bus ID: 00:02.0 chip ID: 8086:5917
Device-2: IMC Networks USB2.0 VGA UVC WebCam type: USB driver: uvcvideo bus ID: 1-5:3 chip ID: 13d3:5755
serial: <filter>
Display: x11 server: X.Org 1.20.8 compositor: kwin_x11 driver: intel unloaded: modesetting alternate: fbdev,vesa
display ID: :0 screens: 1
Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 506x285mm (19.9x11.2") s-diag: 581mm (22.9")
Monitor-1: eDP1 res: 1920x1080 dpi: 157 size: 310x170mm (12.2x6.7") diag: 354mm (13.9")
OpenGL: renderer: Mesa Intel UHD Graphics 620 (KBL GT2) v: 4.6 Mesa 20.1.7 direct render: Yes
Audio: Device-1: Intel Sunrise Point-LP HD Audio vendor: ASUSTeK driver: snd_hda_intel v: kernel alternate: snd_soc_skl
bus ID: 00:1f.3 chip ID: 8086:9d71
Sound Server: ALSA v: k5.8.6-1-MANJARO
Network: Device-1: Intel Wireless 8265 / 8275 driver: iwlwifi v: kernel port: f040 bus ID: 01:00.0 chip ID: 8086:24fd
IF: wlp1s0 state: down mac: <filter>
Device-2: Realtek RTL8153 Gigabit Ethernet Adapter type: USB driver: r8152 bus ID: 4-1.3.4:4 chip ID: 0bda:8153
serial: <filter>
IF: enp56s0u1u3u4 state: up speed: 100 Mbps duplex: full mac: <filter>
IP v4: <filter> type: noprefixroute scope: global broadcast: <filter>
IP v6: <filter> scope: link
IF-ID-1: tun0 state: unknown speed: 10 Mbps duplex: full mac: N/A
IP v4: <filter> scope: global broadcast: <filter>
IP v6: <filter> virtual: stable-privacy scope: link
WAN IP: <filter>
Drives: Local Storage: total: 476.94 GiB used: 349.68 GiB (73.3%)
SMART Message: Unable to run smartctl. Root privileges required.
ID-1: /dev/nvme0n1 vendor: Samsung model: MZVLW512HMJP-00000 size: 476.94 GiB block size: physical: 512 B
logical: 512 B speed: 31.6 Gb/s lanes: 4 serial: <filter> rev: CXY7501Q scheme: GPT
Message: No Optical or Floppy data was found.
RAID: Message: No RAID data was found.
Partition: ID-1: / raw size: 459.59 GiB size: 451.37 GiB (98.21%) used: 349.68 GiB (77.5%) fs: ext4 dev: /dev/dm-0 label: N/A
uuid: db854aac-7229-47ea-a7f7-3759e8d8ecf5
ID-2: /boot/efi raw size: 300.0 MiB size: 299.4 MiB (99.80%) used: 424 KiB (0.1%) fs: vfat dev: /dev/nvme0n1p1
label: N/A uuid: 0D20-FD74
Swap: Kernel: swappiness: 60 (default) cache pressure: 100 (default)
ID-1: swap-1 type: partition size: 17.05 GiB used: 1.8 MiB (0.0%) priority: -2 dev: /dev/dm-1 label: N/A
uuid: 589c0035-943f-4204-97cb-7c92a61e008f
Unmounted: ID-1: /dev/nvme0n1p2 size: 459.59 GiB fs: crypto_luks label: N/A uuid: 090603d0-d1e0-4d7b-8f76-beca97122ab2
ID-2: /dev/nvme0n1p3 size: 17.05 GiB fs: crypto_luks label: N/A uuid: a14c2250-047f-4a75-b878-dadced3ad126
USB: Hub: 1-0:1 info: Full speed (or root) Hub ports: 12 rev: 2.0 speed: 480 Mb/s chip ID: 1d6b:0002
Hub: 1-2:34 info: VIA Labs USB2.0 Hub ports: 5 rev: 2.1 speed: 480 Mb/s chip ID: 2109:2817
Device-1: 1-2.2:36 info: VIA Labs USB2.0 Hub type: Billboard driver: N/A interfaces: 1 rev: 2.0 speed: 480 Mb/s
chip ID: 2109:0100 serial: <filter>
Hub: 1-2.3:35 info: VIA Labs USB2.0 Hub ports: 5 rev: 2.1 speed: 480 Mb/s chip ID: 2109:2817
Hub: 1-3:39 info: VIA Labs Hub ports: 4 rev: 2.1 speed: 480 Mb/s chip ID: 2109:2210
Device-1: 1-3.2:40 info: VIA Labs USB2.0 Hub type: Billboard driver: N/A interfaces: 1 rev: 2.0 speed: 480 Mb/s
chip ID: 2109:0101 serial: <filter>
Device-2: 1-5:3 info: IMC Networks USB2.0 VGA UVC WebCam type: Video driver: uvcvideo interfaces: 2 rev: 2.0
speed: 480 Mb/s chip ID: 13d3:5755 serial: <filter>
Device-3: 1-8:4 info: Intel Bluetooth wireless interface type: Bluetooth driver: btusb interfaces: 2 rev: 2.0
speed: 12 Mb/s chip ID: 8087:0a2b
Device-4: 1-9:5 info: Elan Micro ELAN:Fingerprint type: <vendor specific> driver: N/A interfaces: 1 rev: 2.0
speed: 12 Mb/s chip ID: 04f3:0903
Hub: 2-0:1 info: Full speed (or root) Hub ports: 6 rev: 3.0 speed: 5 Gb/s chip ID: 1d6b:0003
Hub: 3-0:1 info: Full speed (or root) Hub ports: 2 rev: 2.0 speed: 480 Mb/s chip ID: 1d6b:0002
Hub: 4-0:1 info: Full speed (or root) Hub ports: 2 rev: 3.1 speed: 10 Gb/s chip ID: 1d6b:0003
Hub: 4-1:2 info: VIA Labs USB3.0 Hub ports: 4 rev: 3.1 speed: 5 Gb/s chip ID: 2109:0817
Hub: 4-1.3:3 info: VIA Labs ports: 4 rev: 3.1 speed: 5 Gb/s chip ID: 2109:0817
Device-1: 4-1.3.4:4 info: Realtek RTL8153 Gigabit Ethernet Adapter type: Network driver: r8152 interfaces: 1
rev: 3.0 speed: 5 Gb/s chip ID: 0bda:8153 serial: <filter>
Sensors: System Temperatures: cpu: 46.0 C mobo: N/A
Fan Speeds (RPM): cpu: 3500
Info: Processes: 244 Uptime: 1d 2h 24m Init: systemd v: 246 Compilers: gcc: 10.2.0 Packages: pacman: 1300 lib: 352
flatpak: 0 Shell: Bash v: 5.0.18 running in: konsole inxi: 3.1.05