I think I can help you a little along the way of what the problem here is exactly.

First let me start of by saying I know exactly what you mean. I've been there.

The problem here is that you are under the impression (or illusion, rather) that you can think your way in and out of social situations, as if they are something to be intellectually 'solved' and gotten through in a certain way which is then again intellectually categorized by you as a 'succes' or a 'failure'.

This is, of course, not how any social situation works or will ever work. Social situations are something that, just like listening to a piece of music, you do/are in because of the experience, not because you want or have to get to the end of it.

The overall problem is that you think about social situations before they are happening, thereby trying to solve them or control them, which you can't. At least while also being genuine and authentic. Something which every human being has almost like a 6th sense of picking up on.

Science doesn't yet seem to have come to the point of really researching this because for that a paradigm shift would be needed that is on it's way but not quite there yet.

My personal everyday interpretation (but, as someone with a degree in psychology) is that you have learned or thought yourself that life can be controlled by thinking through anything and everything you subjectively see as a problem. This is a problem because life can't be controlled, because you can't even control yourself on a very fundamental level. And you are way to emmotionally dependent on having situations go the way you thought about them in advance.

As someone who also highly recommends and is experienced in different mindfulness practices, I recommend looking into this, there is a lot of popularized stuff out there, but in it's most basic and essential form, it really is a 90-95% percent fix to the whole social anxiety issue when practiced correctly.

Good luck with whatever you choose to work with!