Why not try a territory here on Stacker News? (Especially if there were semi private territories?)

Discourse is fine, but you will still end up doing a lot of moderation. Stacker News has less need for moderation because of the sats. Also, users could zap you and each other for helpful responses. Also post+comments format lends itself to discrete user issues.

Biggest obstacle I can see is that users need sats to post. Maybe this can be fixed with some freebie posts in the territory.

Other obstacle is that you probably don't want all your forum discussion happening in the middle of stacker news. But might be solvable if there was a way to make a territory not show up in the main feed.

Anyway, if you are looking to build a community around a bitcoin product, maybe consider doing it here.