The problem seems to be with dual domain support? If the forum switched to being onion-only, would that fix the issue?
Regardless, Discourse heavily relies on javascript. Could this be a good opportunity to switch to something like phpBB, which to my knowledge works okay without javascript? Or would that be too burdensome?
edit- I guess if it was onion-only, search engines would not index it, so it would be harder to do the self-support-first policy.
Burdensome. Replacing one issue with a completely different forum software probably trading for tons of new issues plus loosing old contents, user accounts or migration (if even possible), whatnot.