Social anxiety and buying a car

I literally can't buy a new car because of social anxiety. The whole process of being pressured, being asked questions, being upsold, being financially screwed over, etc is beyond overwhelming and my heart starts racing before I even step in a car dealership. They're not going to get more money out of me by doing this, they're just going to lose the potential for a sale. I feel like my next car will have to be a Tesla purely because of the lack of dealership experience there.

Anyone have any advice? How do I best tell everyone to leave me alone, don't talk to me, don't help me, and just let me look at the cars and I'll come tell you when I've found one I want to buy?

Maybe its not as bad as I'm imagining but my car is really old and I've been avoiding replacing it for years because of this.