Hey, same story with me, started it practicing last summer, with chords too and dotted rhythms, just one question, have you tried ALL possible rhythms combination/pattern possibilities? I have stopped practicing because I don't like it anymore haha, but I'll probably start practicing again. Try every combination/pattern you can think of, 1 slow 3 fast, 1 slow 2 fast 1 slow, 1 fast 2 slow 1 fast, etc.
When doing the chords, pay close attention to your position, hands and ELBOW. In my experience, wrong elbow position is the main reason/cause of wrong notes, how to tell if your elbow is raised in the right position? when your 5th finger is well placed, parallel to the keys, and when your elbow is more or less at the same height of the keyboard.
Practice passages as slow as possible with completely 0 mistakes and 0 hesitations.
Practice with different finger attacks? (is that the term in english? I'm just translating directly from Spanish

) that's with finger raised, pulling fingers from the keyboard,etc.
Also, watch your 2nd finger, in my case the 2nd finger was the one that had more trouble playing cleanly.
Speed up gradually, with metronome. Also, the faster you play it the bigger your impulses will be.
When you practice with dotted rhythms, start playing bigger passages until you can play the whole etude with one rhythm pattern/combination with 0 mistakes and 0 hesitation, until you can do the whole etude with 1 rhythm. And practice playing it from start to end very slowly, really slowly, I'm talking about 40-50 bpm the SEMIQUAVER, yeah, it takes a lot of patience, but believe me, your concentration capacity will boost immensely. Also with 0 mistakes and 0 hesitation. * notice how I said to practice it slow twice?

it's THAT important.
And, if you practice by repeating any passage in any way, always repeat with 0 mistakes and 0 hesitation.
That's how I practice it.