I totally understand your desire for a community that allows you to discuss classic trek without worrying that your enjoyment of new series will be lessened if you read spoilers. Reddit has a big enough user base to have separate subreddits for each series. Lemmy’s not there yet.
think there is a way to make any forum spoiler-avoidable, especially where very current episodes are at play. Sensible titles (e.g., including the episode discussed) would go a long way toward helping with this.
Lemmy also ostensibly supports spoiler tags
spoilers withinBut not every client supports them. Hopefully as clients improve, support will be universal.
Getting people to use those where appropriate might also help.
I look forward to seeing how this and other trek communities develop, and I hope that your experience improves.