Related to this I have the same problem. I think the cause is that system sees LG monitor disconnected when it is actually just turned off. It is not a critical problem but is really bothersome.
$ inxi -GSa
System:
Host: siavosh-ms7b18 Kernel: 5.19.7-1-MANJARO arch: x86_64 bits: 64
compiler: gcc v: 12.2.0 parameters: BOOT_IMAGE=/boot/vmlinuz-5.19-x86_64
root=UUID=0baecea2-6a30-4ac4-ab13-4c58bcf15c2f rw quiet
udev.log_priority=3 zswap.enabled=0
Desktop: KDE Plasma v: 5.25.5 tk: Qt v: 5.15.6 wm: kwin_x11 vt: 1
dm: SDDM Distro: Manjaro Linux base: Arch Linux
Graphics:
Device-1: Intel CoffeeLake-S GT2 [UHD Graphics 630] vendor: Micro-Star MSI
driver: i915 v: kernel arch: Gen-9.5 process: Intel 14nm built: 2016-20
ports: active: HDMI-A-1 empty: DP-1,HDMI-A-2,HDMI-A-3 bus-ID: 00:02.0
chip-ID: 8086:3e98 class-ID: 0380
Device-2: AMD Ellesmere [Radeon RX 470/480/570/570X/580/580X/590]
vendor: Sapphire Nitro+ driver: amdgpu v: kernel arch: GCN-4
code: Arctic Islands process: GF 14nm built: 2016-20 pcie: gen: 3
speed: 8 GT/s lanes: 8 link-max: lanes: 16 ports: active: HDMI-A-5
empty: DP-2, DP-3, DVI-D-1, HDMI-A-4 bus-ID: 01:00.0 chip-ID: 1002:67df
class-ID: 0300
Display: x11 server: X.Org v: 21.1.4 compositor: kwin_x11 driver: X:
loaded: amdgpu,modesetting alternate: fbdev,vesa gpu: amdgpu,i915
display-ID: :0 screens: 1
Screen-1: 0 s-res: 4480x1080 s-dpi: 96 s-size: 1182x285mm (46.54x11.22")
s-diag: 1216mm (47.87")
Monitor-1: HDMI-A-1 mapped: HDMI-1-1 pos: primary,left
model: Samsung S22D300 serial: 810242609 built: 2014 res: 1920x1080 hz: 60
dpi: 102 gamma: 1.2 size: 477x268mm (18.78x10.55") diag: 547mm (21.5")
ratio: 16:9 modes: max: 1920x1080 min: 720x400
Monitor-2: HDMI-A-5 mapped: HDMI-A-4 pos: primary,right model: LG
(GoldStar) ULTRAWIDE serial: 424803 built: 2017 res: 2560x1080 hz: 60
dpi: 81 gamma: 1.2 size: 798x334mm (31.42x13.15") diag: 869mm (34.2")
modes: max: 2560x1080 min: 720x400
OpenGL: renderer: AMD Radeon RX 580 Series (polaris10 LLVM 14.0.6 DRM
3.47 5.19.7-1-MANJARO) v: 4.6 Mesa 22.1.7 direct render: Yes