i think it's a three-way problem between asus bios, ryzen, and linux kernel. i had a similar problem that was pinning my PN51 to kernel 5.19.16 (in my case, though, i didn't get a garbage screen, i just got a hard freeze).
i am deathly afraid of bios upgrades, but i swallowed hard and took it - and then the sleep problem went away, and i went back to floating on kernel 6.
but i just got a fanless enclosure, and once i flipped off the fan monitoring, sleep stopped working again - now it hard reboots by itself without any obvious clue in the logs.
the fanless life is more valuable to me than sleep - i have an ssd and don't run persistent services, so i don't care enough to keep fighting it. but there's definitely a tussle in there.
i have a 2017 macbook on which pop won't install (installer crashes). so it runs ubuntu. the experience is maddening compared to my (non-system76) pop box