The 6.6.x kernel series is LTS and should be fine as a downgrade target (6.7.x not so much so). Unless there’s something specific from the newer kernel versions that you need to drive that system, there shouldn’t be any issues. I’m still on a 6.6-series kernel.

That being said, you could try troubleshooting this from the bottom up rather than the top down.

First, use lspci -v to verify that the device is being correctly identified and associated with a driver.

Next, invoke alsamixer and make sure everything is unmuted and your HD audio controller is the first sound device. The last time I had something like this happen to me, the issue turned out to be that the main soundcard slot was being hijacked by an HDMI audio output that I didn’t want and wasn’t using, and that was somehow muting the sound at the audio jack even when I tried to switch to it. A little mucking around in ALSA-level config files fixed everything.

Provided Fedora has the appropriate packages (and I expect they do), I can’t see why not. But see if there’s any distro-specific documentation on switching first.

Wayland’s nvidia support is improving over time, but although it’s becoming less popular, X11 isn’t likely to be completely deprecated anytime soon—I’d expect any mainstream distro to still at least have it as an option a couple of years from now, to handle corner cases Wayland still doesn’t support.

The last X11 stable version bump on my distro was about a month ago, to 21.1.16, so it isn’t like it’s abandonware or anything.

Wild idea: check the condition of the SDD (presumably) that you’re trying to install to. After all, an installation has two endpoints, and if the target disc is on its last legs and throwing SMART errors, it ain’t gonna be too happy getting written to.

Did you make sure that Nouveau was not loading? If both drivers are on the system, Nouveau usually ends up taking precedence unless it’s been blacklisted. Also, if this is a laptop type with a hybrid graphics setup, you may need additional software to manage the handoff between GPUs (optimus, bumblebee, etc.)