Upgrade salsa-runner.debian.net to bullseye?

I recently spent some time tracking down a reduced test case for the long-running issue with locale warnings from man in Salsa CI. This turns out to be reproducible outside of Salsa CI by simply running a privileged Docker container in a buster VM, and appears to be a bug that was fixed in bullseye's version of Docker by causing privileged containers to use a docker-default AppArmor profile rather than unconfined; it is not reproducible in bullseye's version of Docker.

The sensible paths I can think of to get this fixed seem to be:

• cherry-pick Docker fix into buster-proposed-updates
• backport bullseye's Docker wholesale to buster-backports (though I don't know if this would be possible)
• upgrade salsa-runner.debian.net to bullseye

Before going down complicated roads involving updating oldstable's Docker somehow, it occurs to me that the Salsa admins might want to be on Debian stable for other reasons anyway, and if that's already planned then perhaps it would make more sense than figuring out how to patch oldstable for this. Would it be feasible to upgrade salsa-runner.debian.net (is that the only runner that runs privileged Docker containers? I'm not quite sure how to tell) to bullseye?