Making friends as an adult is awkward for everyone. Be the one who sends the second invite.

Adult friendship has no built in structure, so it depends entirely on somebody being willing to look keen. The first invitation gets sent reasonably often. The second one, after a pleasant evening that nobody followed up, is where almost everything dies, because both people are waiting to avoid being the eager one. Whoever sends it usually gets the friendship.

Think of somebody you got on with and never saw again, and send the second invite now. Make it specific and easy, a time and a place. The small risk of looking too interested is the entire cost, and it is lower than you think.