80 bpm, but many notes per beat? Are we talking like one note per metronome click or like 16th notes or what?
I can think of a couple of things you might enjoy trying, and I do want you to spend more time with things you enjoy vs things which aren't as fun.
#1 If you're trying to learn a picking thing, maybe try learning the thing perfectly with your picking hand only until it's as easy as breathing. Then slow way back down again and learn the other hand. One challenge at a time. When I do this kind of thing I take my left hand and lay a finger across the strings on a harmonic, usually at the 12th fret. This way it feels like I'm picking fretted notes (vs picking muted strings). You can also tune the strings down a whole step to minimize fatigue, but I usually don't bother.
#2 Try spending some time practicing with no "autopilot", in other words be in control of every note one at a time. Slow down so much that you can always think ahead to the next note. It should be literally impossible to make mistakes practicing this way. I don't always practice like this, but when I do I always see obvious improvements in economy of motion.
#3 Maybe tension is making muscular control more complicated for you. Frequently relax and massage your forearms, front and back. Or maybe this isn't a problem at all, how would I know? Just another thing to think about.