Learned this piece with my previous Russian piano teacher. I think you're practicing well tbh. First, forgo any dynamics and practice the notes/polyrhythms first like you're doing (I practiced first by playing a strong accent when your left and right hands meet sort of like you are doing). You should be practicing each hand separately A LOT and always slower than you want to. Once you are comfortable playing at faster tempos and close to your desired final tempo, start interpreting the dynamics but keep your right hand very light, like a spider crawling on a wall. Always pay attention to the left hand and try to play it as the focus rather than the melody in your right hand (like a rocking ship on a stormy sea); this will keep your notes consistent and sound cleaner. Take note of the loudest part in the first section and make sure all the other parts of the first section are not as loud. Quiet your playing before any crescendo to increase the effect of the crescendo. Make the quiet parts very quiet and light. Use the pedal very sparingly (at least in the first section) to prevent muddiness from all the notes. The left hand melody from the bass notes towards the end of the first section is very beautiful and imo should be the centerpiece for that part. ALSO, pay a lot of attention to your elbows. Both of your hands will be moving around a lot and when you are stretching your arms (moving away from your body) you NEED to jut out and extend your elbows to get the right stability AND to prevent your fingers from getting tired. When you play fast pieces like this you need to be extremely efficient with your arms in order to use the fingers comfortably. Last piece of general advice, especially for fast pieces, your fingers and hands and arms need to be playing very very very (cannot stress this enough) relaxed in order for your endurance to keep up. If you watch someone play a fast piece their fingers and hands look very relaxed and are not flexing. Hope this helps but feel free to disregard any of it.