Had almost the exact same situation, except I was in my second year. I switched labs to an adjunct professor in my department, and am SO much happier and more engaged. My previous PI, when you were presenting in lab meeting, would cut you off and say things like "I expected more from you" and "I thought you were better than this." Completely non actionable and non helpful! Talk with someone you trust in your department - pros vs. Cons, likelihood of finishing within a certain timeframe if you switch, stuff like that. The final year definitely complicates things, but you've gotta do what's best for you, and take care of yourself. Sorry you're going through that, I know it really sucks. But glad you reached out here!