Which I just now (after posting) noticed was already mentioned in a different comment. Sorry!

I’m guessing the user who made that other comment is on lemmy.world? I can’t see any comment other than yours, and LW has known issues with federation (issues that would be fixed if the instance weren’t 5 version behind…) that mean I probably won’t be able to see it for about 2 days right now. So thanks!

I haven’t looked into the suggestion in great detail yet, but I will say I’m already running as a non-root user (USER node is a line in my Dockerfile). I’m not sure what a seccomp profile is, but in case it wasn’t clear from the original post, I just want to emphasise that the current configuration works in Docker on my Windows PC. It’s only on the Synology NAS that it fails.