Idk sounds like you're giving these tasks way more reverence than they deserve.

Walking into an interview, shaking hands, smiling. It's easy. You physically have the skills to do it. Undoubtedly. But it seems like you build up the task SO MUCH, that it turns into something that you don't think you can do.

Eg. Online application - "Why are you passionate about retail?" is a super easy question to answer. Easy.

But when you build up the "What if I answer wrong?" "I NEED to answer this well!" and all this other stuff, suddenly the task changes from Answer basic question to Write a perfect piece or FAIL.

With my lack of a psych degree, I suggest breaking down the tasks, and noting exactly what the physical tasks are. Make an effort to forget the consequences, or expectations, or anything else. Look for the exact task, and complete in a vacuum, forgetting anything else. Answer the question, forget about the job.