When you reach mastery you will usually end up breaking most rules. For starters, rules are meant to be one size fits all, but every body is unique which leads to different biomechanics. I knew a pianist who played Grieg concerto at the BBC Proms but she could barely stretch an octave. How she could play all the Chopin etudes from age 9 blows my mind.

Speaking of Chopin his first teacher wasn't much of a pianist and realised Chopin's ceiling was far greater than his own so left him to his own devices wrt technique. Chopin ended up unlocking new techniques on the keyboard which he crystallised in the etudes. He essentially wrote them for himself.

You will see rule breaking common amongst masters of a skill. In fight sports some of the best boxers have all kinds of bad habits - Inoue Naoya doing massive wind ups and Muhammad Ali dropping his hands. The rules are there to help us reach mastery but they shouldn't shackle you either.

To quote Bruce Lee

"Man is constantly growing, and when he is bound by a set pattern of ideas or ‘Way’ of doing things, that’s when he stops growing."

On the subject of Gould his touch is very fussy (although characteristic) and his humming can be frustrating at times. I prefer Perahia's Bach