I have a Gigabyte motherboard too, an Aorus Master b550. It was my first time going with their brand, and I'm ambivalent. The hardware seems nice. Their BIOS do seem a bit buggy, but I don't know how it compares to anything else this decade. I tried contacting their customer service to tell them their @bios tool doesn't work anymore, and it was a complete waste of my time.

On the other hand, why wouldn't this likely be an AMDGPU driver issue? I suppose I should try booting into Windows and suspending from there, just to see if it's reliable. I could also try backing off my fclk frequency, and disable resizeable BAR for the laughs. I could even go as far as swapping my older Nvidia GPU back in and see if that suspends and resumes ok. I'm expecting a new born baby this week, so it's not like I have anything better to do!

I don't like producing e-waste, but if I conclusively knew it was a systemic Gigabyte issue, I would seriously consider switching to a new motherboard from another vendor. I built this desktop after being in the hospital ICU for 5 days, and promised myself I wouldn't spare any expense. I also expect it to last the next decade, and so I don't want to be annoyed by it long term...

Would you be able to share the details of your script? Or does it simply switch to a virtual terminal before suspending, then switch back after resuming?

I was inspired this morning to try, and switching to a virtual terminal before suspending seems to work in my case!

  [Unit]
  Description=Switches to a TTY before suspending
  Before=sleep.target
  StopWhenUnneeded=yes
  
  [Service]
  Type=oneshot
  RemainAfterExit=yes
  ExecStart=/bin/bash -c 'fgconsole > 
  /tmp/fix_resume_active_console'
  ExecStart=/usr/bin/chvt 1
  ExecStop=/bin/bash -c '/usr/bin/chvt $(cat 
  /tmp/fix_resume_active_console)'
  
  [Install]
  WantedBy=sleep.target