You just describe perfectly the phenomenon of what's known by academics as the "third place." Historically, this used to be social clubs that no longer exist in recent decades. I forget the exact list of attributes, but the third place involves consistent, low stakes interactions over a defined period of time (just like you described).

I think bumble BFF suffers in that friend dates don't have a lot of forward momentum with a platonic stranger unless you have a non awkward routine established like going to the dog park every sunday.