there's no real way to practice social interactions in a safe setting
There are small talk opportunities if you know where to look.
Dog parks are my favorite. Bring your dog, make small talk with the other owners, get to know some of them. It's a low stakes environment that doesn't cost any money, allows you to exit at any time, guarantees at least one shared interest or commonality with people who live near you. You don't even have to talk to people the first few times you go, and can build up comfort/familiarity in the specific place before you take the next step of striking up a conversation with another regular you see a lot.
Another option is where unrelated parties might mingle in shared space: communal tables or bar seating at coffee shops or bars or parks or even restaurants. These fleeting interactions might help practice the skills of small talk, enough to where it's easy to have conversations with strangers.
And sometimes you can outsource the actual cold approach to the extrovert strangers you might encounter, by giving them something to talk about. A baseball cap with your university, a T-shirt with your favorite band from a tour you saw live, a tattoo of something fun, other items of clothing or accessories that might attract positive attention. Sometimes people will say something about it, and then you can talk about a shared interest or background at that point.
Lines and waiting rooms are also sometimes good places to pass the time with conversations. It's a little harder now than 20 years ago, with the rise of smartphones, but it's still a place where people might be bored and appreciate a little conversation to mix things up.