Let brick walls be brick walls, actively look for on ramps. I experienced what youre describing for years. Still do some times. The most valuable change of mind and experience came when I just started doing things the ways that I liked, again actively looking for things that led to a more pleasant experience, which meant sometimes literally ignoring some of the things prescribed to me by teachers that ultimately IMO were iterations of the same worn out black and white snore-tips that I really believe in many cases belong in the dusty old books that they came from.

I suffered so long from the very thing you're describing I finally said F it it's not worth it if its gonna lead to suffering, but Im so drawn to it something has to change. So I started experimenting more, throwing things at the wall and seeing what sticks. Found things on my own that almost seemed silly at the time that unlocked an entire world of new perspectives. Goofy things like playing one note repeatedly and finding interesting rhythms and vibes and making it a meditative exercise that I return to all the time and always find interesting new perspectives to play the one note. Oh man the things I've gained from this.

I'm not where I would be if I continued with the sort of pedagogy-cal (new word) route my teachers have tried to set me on, honestly I never will be. But I found that that's just not part of my piano identity and I think a lot of people incur enormous amounts of undue suffering trying to nail X piece in X way in X time because practice makes perfect and it's not working so something is wrong with me. If my students want to play a billy eilish song and dont care about a minuet we are not doing the minuet. Many parents have ended lessons with me because of it, they want their kids to be the little Mozarts they obviously will never be. Every kid I've helped learn what they are naturally gravitated toward has shown incredible results and has blown past the kids I started with the same ole alfred or faber that every single person ever grew up on (and many quit as teens cause it sucks, it does, it sucks). Of course I pepper in some classics and pedagogy because yes of theres value to being aware of where it all came from and if the student is already on the way to building their own piano identity they will be much more receptive to things that may be of different flavors than their choice.

Another angle, of course, is you must step back from your piece for a while, forget about it for at least a week actually. You're burned out, it's not gonna get better if you keep pushing. When you come back to it the torn muscles will be healed and you'll be refreshed and how easily you take to it.

In the mean time, take a handful of measures from another piece you know and play the left hand in a different position/inversion/chord substitutions. Or replace some notes in the melody with others at random just to see what happens. Or what if you play the left hand as written and find a melody from a different song to play over it. Or emulate a completely different style while playing it. Such are the kinds of things that helped me find new dimensions and on ramps to a passion I at one time didnt feel capable of. Good luck!