No, you need regular events, same place twice a month. That's the killer for social clubs like this. Just have a regular date in the diary and if people are free they can drop in.
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.
Its funny because you described liberal Freemasonry: mandatory attendance twice a month. Forcing yourself to go and feeling the honor of being part of a group has been great for me.
I'm sure other groups have that kind of rule too, but the mandatory part is what makes it special.
Well I wasn't suggesting mandatory attendance to every event, but I think if someone doesn't show up for say 2 months their space should be freed up for someone else.