Pick meet-ups with a purpose you would enjoy anyway.
A walk, attraction, gaming event or day trip gives the group an actual reason to be together. That removes some of the pressure to create entertainment purely through conversation.
It also means you already know something about the people who chose the same plan: at minimum, they were interested enough in the activity to turn up.
Friendship in your 30s needs repetition more than intensity.
You do not need one huge emotional conversation on day one. You need names becoming familiar, small jokes carrying over and another reason to interact.
A community around the meet-up makes that repetition easier because contact can continue between events.
Do not measure success by whether you leave with a new best friend.
A first event can be useful if you simply recognise more people afterwards. Friendship can grow from the second, third and fourth interaction once the pressure of being complete strangers has gone.