Social anxiety (fear as you've contextualized it) is just a malfunction of the ego. Your worrying about how others might perceive your actions is getting in the way of you committing any actions at all. Everything we do is a calculated risk to some degree or another. Just going to work, supposing we work around others, puts us in contact with many social situations that, if we were to put it to paper and overexamine it, might seem daunting. But as we've matured, we've grown so accustomed to these interactions that we pay them no heed. Where you're having trouble is that you've started to overanalyze at a point behind where others do.
What people with this kind of anxiety do is tell themselves that they have something to lose, should they be unsuccessful in socializing. The reality that I have to remind these kinds of people of is that, to be blunt, they don't. Their shut-in nature has made them tabula rasa to the outside world. They have no social coin to lose. I have to also temper that seemingly-depressing statement by telling them that they therefore have everything to gain.
Don't convince yourself you have worth. Give yourself worth. Not materially, of course. No amount of money or possessions can fix that. What I mean to say is go out and do things for others. Even if it's just talking to someone at a social gathering (once we're done with the lockdowns, of course). Cheer someone up by acknowledging them. As how their day has gone. Even if you don't give a rat's arse, ask anyway. People tend to feel better when they have someone to talk to. And when you start to see people feeling better as a result of your direct actions, you'll build that self-confidence you need.
Actions speak louder than words, anon.