Things change pretty quickly there, so the safest update is still to check the apps once you’re in town: Grindr and Romeo usually show plenty of locals and escorts, and you can get a feel for who’s active that week. Be clear about expectations before meeting, and use a bit of caution with profiles that look too polished or pushy.
For venues, Bucharest doesn’t have a huge gay scene, but there are a couple of bars/clubs and occasional events. I’d also recommend checking recent Google reviews/social pages for places before going, as opening nights and crowds can vary a lot.