How do you deal with coworkers trying to take over areas of your work?
Especially if they are very arrogant or entitled about it?

Cant talk to the boss, boss doesnt care about the issue. Has repeatedly lead to drama in the past with this guy. He likes to point at his chest while legit screaming "I'm the expert! This job belongs to me. Its mine because I was here first."

Even though the job was given to me.

And worse when I push against this nonsense my boss tells me to stop creating drama.

Like wtf. You gave me a job to do, and this asshole is horning in on my work and taking credit.

I got put on backend office work (because I cant afford to take even a day) while I recover and dont know how to deal with this dickhead.