Reading this post made me look into HDR more, and I do think it provides a very noticeable improvement.

I run on a cheap 4k HDR TV/monitor, and HDR has never looked right in games, but I noticed in the monitor settings that there is a calibration program you can download and use to calibrate windows to your display. It turns out my white level was way off, so everything looked way to bright. Properly adjusted it looks very good now.

FWIW, I have never been able to get HDR to work with No Man's Sky either, but now that looks really nice.

I use Willybach's 4k texture pack, which makes Valheim look amazing. With HDR now it looks even more amazing. So much so that I sailed past my base last night because I was mesmerized by the moonlight reflecting off the trees and terrain.