Then do the more unique events on a different day (and let members suggest/ organise events too).
Friendship is repetition with the same group. Make it easy on people by meeting at the same time, maybe changing venue within a small area.
A group chat can be the clubhouse these days provided everyone meets regularly. I'd revoke membership from frequent no-shows. You want to limit groups to around 70 people too. Some research says above that cliques form.