Power games at work

I have some issues with my boss and it's upsetting me.

My boss has two offices, one where they actually work, and an old one they never work in any more, so I get to work in that old one on my own, which I'll admit is a bit of a luxury. After 3 years though, the office still has their name on, and is full of their junk. I am not permitted to refer to it at "my" office.

When my boss visits the old office where I work to speak to me, they act like it's theirs, they laugh at me, turn off the light that I'm using, start using my mouse and keyboard in front of me etc, and it's just unsettling not having my own space or having any control when they are around.

I have quite some health anxiety and so I don't like anyone to touch my stuff. I have an alcohol spray that I have to use after they visit so I don't spent the rest of the week worried that I'm going to get sick from their germs, but literally no-one else would touch my stuff without permission as they know I will be horrified. IT get a free pass when they are fixing something ;)

If feels like my boss doesn't see me as a person, just an object of no consequence, that's squatting in their second office. They don't respond well to confrontation and know I have anxiety but they seem to get a kick out of making me uncomfortable and having power over me :(. It's not just the office stuff, I don't get credit for what I do and get unfavorably compared to people less skilled and experienced just because those people are favourites who fit a certain demographic. It makes me sad and question my worth, not only at work but in general.

Not sure if there's anything I can do except leave this employer but things are a bit complicated on that front... anyone got any helpful words for me?