In Kubuntu, I was able to get my HT Omega Fenix sound card to work (switching profile to the correct spdif output), but the Audioengine D3 only works at 100% volume. This is the kind of thing that it's like cool if it's a one time thing. But you just know if it can't work out of the box for something like a USB DAC, it's not gonna be all fun down the line for other more specialized hardware I try to use.
I also tried getting 4:2:0 subsampling to work in an X11 session in Kubuntu. I was able to get there editing xorg.conf (which is annoying having to edit a config file - no option for it in the Nvidia X Server settings). 4K120 over HDMI works in principle, but then Night Light's hue becomes green instead of red.
Additionally, Kubuntu (KDE Plasma) was the best looking and functional desktop I found when browsing various ones (it has the taskbar customization settings I want built in), but it still just feels kind of cheap to me. The early 2000s looking pngs everywhere, the transparency and jiggling in window dragging, very basic looking UI icons. It feels more cute and amateurish rather than serious, visuals and design wise.
The need for editing configs to get to basic functions I expect in Windows really went against my expectations this time around trying Linux. I really bought into the LTT Linux hype. But it genuinely surprised me just how sketchy the experience was for my needs.
I understand it's free software which is awesome, and that Linux is necessary for the world and a solid backup against Windows, but all of this is not working for me. Gonna stop my search for now after trying CachyOS and Kubuntu. Maybe when SteamOS is in full wide-release mode I will try that.
Thank you everyone.
