Perhaps some of you had the same issue I did, using the nvidia-deck image, and finding that steam remote play didn’t work from gaming mode, with a black screen on the client. While sunshine/moonlight remains an option, I wanted to get the more native steam remote play working, and managed to figure out the issue and patch it in gamescope.
I submitted a PR both to upstream, and to Bazzite’s fork of gamescope to fix the issue, so hopefully the PR gets some dev’s eyes on it and the feature will work out of the box on Bazzite in the near future.
In the meantime, if anyone needs this feature, check out my commit in the repository from the PR, and if you’re adventurous enough, you can build your own image of bazzite with the fix.