My friends have potlucks at at public parks/beaches. For me I often gather at the local hackerspace which is a collective that I’m a member of. I’m joining another collective that’s a tiny farm and they have potlucks. Theres “bike party” where a bunch of rowdy people meet in the streets, ride bikes for 5 miles or so with music blaring out of special speaker filled bike trailers and we take over both lanes of traffic until we ride to a selected location to throw a dance party.
And I don’t have a spare bedroom. Also most of my friend group doesn’t drink.