Ask strangers to take a photo of you. Most people will happily assist even if they're in their phone bubble.

The photo doesn't have to be anything special. The point is to start an interaction and break their frame long enough to focus on you (without being a jerk).

When you check the photo ask a question, give a complement, or share something about yourself.

Ask to take a selfie with them. If they ask, "why?", just say "I want to capture the moment I made a new friend".

Follow up with another question, complement or story to continue, or take the opportunity to leave on a high note.