I think you need more flexibility in your palm and wrist. Think of a rubber band that takes the shape of the thing you wrap it around - rather than have your hand in a fixed shape, it moulds and flexes to the shape of the chord.
I'm finding it hard to figure out what this means from an execution standpoint. If the wrist goes lower, for example, it becomes harder to articulate the notes.
Also, what do you mean by flexibility of the palm?
More of a lateral rotation as this piece is dealing with wide spaced chords. The direction of movement could be described by placing your hand flat on a table, and rotating your wrist as if you were motioning to wipe the table surface.
The part of the hand between the wrist and knuckles needs to remain flexible, elastic and supple. If the palm becomes too rigid it can restrict the fingers ability to articulate, cause unnecessary tension in the playing mechanism, and also create a disconnect between the transfer of energy from torso to the fingertips. A rigid palm also tends to place undue focus on playing with just the fingers, as opposed to involving the whole arm.
I also noticed during the ascending passages that your entire forearm, wrist and hand tends to shift upwards when you move toward the 5th finger then drop back down when you play with your thumb. Try to use more wrist rotation to get your fingers in position as you move towards the 5th finger, rather than raising and dropping your entire arm.
With regard to LH, here is a good opportunity to practice LH discipline. A lot of long sustained notes. Think slow practice tempo, with quick, snappy, and precise LH movements between notes. The focus being what you do between notes.
It looks like your fingers are tensed/held ready to play when they need to be very relaxed. Your pinky is kind of pointing ahead to the next note, and your fourth is kind of held suspended in the air.
You should scrutinize how to practice it with more rapid tempo but with controlled pauses spotted throughout as required, perhaps even apply rhythmic alterations. The max and min points of the Rh feels like you are still doing a bit of calculation which sometimes produces correcting movements which are disruptive and unhelpful. You can always fast foward your video and see if your slower movements look appropriate.
I feel like I've improved quite a bit in this video. I would really appreciate some feedback, thanks!ETA. Thanks everyone for all of your feedback. It has been really helpful. While I don't expect to get this to performance standard anytime soon, it has been a great learning experience, and I think I've reached farther than I initially expected.
I react to the fact that you mess up quite a lot. To make more progress, you need to practise at a tempo where you make no mistakes. Don't push the tempo until you can play the whole thing through cleanly at your current tempo. You can experiment with a faster tempo in one arpeggio to find the technique, but don't practise messing up. It'll make it more difficult to develop the technique.
The articulation is much improved here. There is better evenness of tone with more assured tone production. Your RH wrist and palm can still use more flexibility.
I think the note errors and hesitations are not from the difficulty of the RH part, but rather because you are unsure of what chord comes next. You have a good idea of techniques the RH requires, now you need to work on the harmonic progression of the passages. You need to know the next harmony, how to get there, what shape your hand needs to take, what distance the LH has to jump, all before you reach the point of needing to play the new harmony. Know where you need to go.