UPDATE: Long story short…I still have no clue. Unplugging my second monitor got the proprietary drivers working properly on KDE Neon, but not on any Arch based distro I tried. I tried kernels from 6.1 to 6.18, and drivers all the way from 470 (disaster) to 595, dkms and open. Followed all the advice on the Arch docs regarding power management, blacklisting, etc…

Soooo…I don’t know. But I’m up and running with a single monitor on an Ubuntu based distro, which isn’t ideal, but right now I’ll take what I can get.