I can't talk to girls

I was that nerdy socially anxious guy in school. Although I've managed to open a little in uni so that I'm more sociable than I was in school I can't talk to girls romantically to save my life. I just don't know what to do! If I see a girl I like at the gym, in a lecture theatre, the library my mind just goes into overdrive with questions like "what do I say after hi?", "how do I escalate/flirt with her without seeming creepy?", "how do I ask her for her number?".

As a result I'm a 22 year old guy who has not had a single romantic interaction in my life and I feel behind compared to my peers because of that. I lack charisma and have no idea how to navigate romantic interactions or as people nowadays would say it "I got no rizz" 😂. All the conversations I do have with a girl just become very boring and platonic and she loses interest in me very fast. I'm scared that I'm gonna turn out to be that 40 year old kissless, dateless virgin.

Physically I'd say that I'm pretty attractive. I've been working out consistently for the last 3 or 4 years now and have a decent fashion sense, and I've been complimented on this before. So I need to improve my social skills/charisma and learn how to navigate an interaction with a girl.

It's like most guys of my age know how to do that and picked it up in their teens, but I missed out because I was too busy playing video games and studying. Anyone got any tips on how I can improve my social skills/charm and learn how to talk to girls?