[burntoutfire]

Is it social anxiety or just anxiety in general? Nothing in what you wrote indicates the social aspect of anxiety. It seems that you just get anxious due to being in high-stakes, high-pressure situation - not because you're being in a social situation (do you get nervous and choke when at a party, or talking to a clerk in a bank? - these are examples of social anxiety).

If it's just general, and fully justified anxiety due to being in high-stakes situation where you have to think on the fly - my advice is that you just need to toughen up. Start putting yourself in situations where you're outside of your comfort zone more often - you'll feel anxiety similar to the one you experience during interviews, and will slowly learn to handle it.

As for the interviewing advice specifically - interviews are free, so you can just do a ton of them to practice. After you do a bunch of them, you'll be able to smoothly introduce yourself and talk about your past work, just thanks to having done that a lot in the past. But, also, practice doing it outside of interviews! Literally prepare to it like you prepare to a presentation you have to do at work. The part of the interview when you introduce yourself and your experience is basically a sales pitch and you have to work on your sales skills to pull it off well enough (You don't have to become a pro sales person, but you definitely have to say more than just "I'm a backend engineer". When I introduce myself during interviews, I generally give a 5-10 minute overview of what I did in my past roles that is related to what the interviewing company's needs).

Also, a nice trick during interviews if you're nervous is to just mention it. If you're visibly underperforming, say something like "sorry, I get nervous during those things" - this will remind the interviewer that you are in fact under a lot of pressure at the moment, and they'll be more likely to help you out if you're stuck, and be more sympathetic to your situation in general.