Ubuntu 22.04.3 New monitor displays "no signal" on startup

Recently I bought a new Dell S2722QC monitor for my PC. I connected it via HDMI. When I start the PC the monitor shows warning "No HDMI Cable". However it works fine with another PC (Windows 10 without dualboot). My setup is Ubuntu 22.04.3 with dualboot (GRUB and gdm3). AMD CPU (so no Intel drivers) and RTX 3080Ti GPU.

When I searched for similar problems I noticed that mostly there are two scenarios, either laptop+external monitor or PC+dual monitors. However I intend to use this monitor as a one and only.

What exactly goes wrong:

• If new monitor is plugged in on the startup firstly it shows "No HDMI cable" error. Then it might either show black screen as if is processing a new connection but switches back to the same error. Sometimes it goes into the loop of constantly switching between black screen and "No HDMI cable".
• If I start the PC with old monitor then disconnect it and finally connect the new monitor it will show black screen for a longer time but still go back to "No HDMI cable".

What I tried to no avail based on other askubuntu answers:

• Reinstall nvidia drivers with sudo ubuntu-drivers autoinstall. Now "metapackage from nvidia-driver-535 (proprietary, tested)" is used. It is marked as recommended.
• Switched to lightdm, tested, switched back to gdm.
• Added "nomodeset" to GRUB so now the entry looks like GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset".

FYI before Nvidia driver update I could plug in new monitor after I had logged in with the old one and the new monitor worked albeit with "base monitor" resolution 1920x1080. While in that state xradr returned only "Screen 0" info without a word about HDMI.

I am a casual user but for me it looks like something on the startup loads wrong and leads PC to ignore the monitor/incorrectly classify it/not send videosignal. Whole situation doesn't make a lot of sense for me since I thought that you could plug in any monitor and it would just work (not speaking of proprietary OS-specific features).

Since this was asked in older threads about similar problems:

1. Secure Boot is disabled;
2. xrandr output is like that:

HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 598mm x 336mm
   1920x1080     60.00*+  59.94    50.00  
   1680x1050     59.95  
   1440x900      59.89  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      60.00    59.94    50.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    72.81    59.94    59.93  
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)