Does this mean that you can’t shut the bathroom door and effectively lock her out of your room when you leave, or when you don’t want her to come in (which sounds like always)?
As for the bathroom stuff I think you have to just deal with it, as in ignore it. If your door can lock, use the toilet paper solution recommended above (if not, sounds like she’ll come in and look for it). Having issues with bathroom timing happens, Issues with bathroom cleaning are also super common. It sounds like she is trying to set you off with her behavior and you’re falling into it.
Your relationship has deteriorated and you’re both coming off of your own separate roommate problems. Try to talk it out and work it out, or if you are “done”, just keep your room secure, keep your half of the bathroom clean, and ignore the rest of her bathroom issues and habits.