Nothing related to screen resolution. Wifi worked via the command-line tools mentioned in the manual, or the KDE interface. Similar for other things. I didn't stick with KDE--I switched to sway--so there were a number of things to deal with because of that, but that won't matter if you do use one.

If you do encounter an issue it will be more work to deal with, because you both have to figure out the underlying issue and then figure out how to fit that into the Nix way of doing things.

The biggest factor is handling downloaded pre-built binaries that assume various libraries will be in typical locations. Those generally require patchelf and then they work fine. I would only recommend NixOS for now for people who are willing to tinker a bit and learn how it works.