Johann Sebastian Bach

Finger independence -> Bach, more Bach, tons of Bach.

playing every day my beloved Chopin and Grieg and Bach and so on.

Meanwhile, the best "finger exercises" for your hands and brain are Bach and Scarlatti. Also Haydn and Mozart if you are feeling "modern". These 2-4 have everything you need for *evenness*

replace Brahms with Bach

I adore complex Bach and Rachmaninoff and César Franck. That's where my heart is.

I would just recommend Bach. It covers all the technical basics and you might absorb a thing or two about counterpoint, which is nice to add in any chorus

I have some of his mazurkas along with a good amount of intermediate-low advanced Bach under my belt.

The few Bach pieces that I've learned to play (and am capable of playing) opened my eyes to fingering and efficient hand movement as you mentioned, and it truly is quite satisfying.

LISTENING to Bach is like speed reading an advanced theoretical physics textbook. There is SO much in there that the simple act of listening at normal speed means you'll miss most of substance.

Whenever I really want to improve my technique and musicality, I study Bach more than Chopin etudes.