This! Debian with Gnome or others is the answer. Take an afternoon to make it yours, then forget it. You can use backported kernels on Debian, to support newer hardware. Try this or upgrade to Debian 13 right now by changing the sourcefile to trixie instead of bookworm. Note : if you use Gnome, let gnome-software handle the updates for you (there’s an equivalent for kde). If you use others, configure unattented-upgrades for automatic updates.

As a 6700XT owner, I use 4k@60Hz (my screens can’t do better anyway). Does that mean I would need to use DisplayPort for better output in the future?

For reference, I have a 6700XT on a 4k videoprojector, and it’s fluid for 4k video and games (but it’s a gaming card). The drivers are excellent and the card is stable. Thus said, I read some web videos through mpv, which is more optimized. On Youtube 4k, it works as well. I’ve tried 8k downsized and it was bit laggy, so I don’t think a 6400 is enough for 8k video. I also had to buy a HDMI cable with more throughput! Videos aside, I think it’s okay for the display only (texts and images), but wait for another reviewer because the 6400 is less powerful, so I can’t confirm. However, if it works on Windows, it will work on Linux.