It feel like I could have written your OP. I've been battling the social anxiety issue for a long time as well, and like you the exposure hasn't done much. Nowadays I can 'perform' better when I go out, but it is still exhausting, and no more comfortable than it was 20+ years ago. I'll still experience visible shakes from the fight or flight adrenaline response being so strong, and the stress will start burning through my stomach if I do too much.

Only in the past year have I finally begun to make any kind of progress, and I would attribute that progress to having been referred to a therapist who appears to be better tuned in to what I need, and is more responsive to what I bring forward during our sessions. As I work through exposure with my therapist we are also approaching what is behind the anxieties, rather than simply trying to deafen myself to the symptoms. This part I am struggling with since I'm not really able to open up, but hopefully I'll get there at some point.

If you feel like something is missing from your exposure experiences, perhaps the support you have is not enough? Getting matched up with my current therapist felt a bit like I went from wandering aimlessly in a maze, to having someone in my earpiece guiding me through that maze. It makes a world of difference.