Before the pandemic, I used to go out alone on purpose just to meet random people. (I'm married.) I know this isn't for everyone, but I got good at it and I enjoy(ed) it. I've noticed however, that this is a skill that can atrophy. It's taken me a little while to get back to my old self in public places.
I'm curious how this can work. What you're describing sounds impossible. You go to a restaurant: how do you have any kind off conversation beyond maybe a joke to someone in a line? My impression is that people are friendly but not interested in anything beyond pleasantries with a rando.
If you're wondering how to start a conversation, a compliment goes a long way.