the Rach 3
Very, very, very difficult. Definitely!
Most difficult? Almost certainly not.
Well! But you can call Rach 3 is the most difficult bunch among all of them right?
For me, I think the Tchaikovsky's 1st Concerto can be on the list, same difficulty with the Rach 3.... agree?
Generally, if yous can't for all repertoires in COMPOSER - I suggest JS Bach. You've need full attention on what the 4-tier melody are happening, which you'll never find such things in the other composer - the top ones are especially the Toccatas and Fugue BWV565 after it is arr. by F. Busoni. Indeed, it sounds like my energietic after arranged to the pianos as it is just magical that Bach can write so many lines that a normal person and compose things like that in the computer! (I mean - Copying lines through orchestration)
I have tried Bach's BWV565 and it took me six years to master it. (I am now in Grade 10 - so I starts playing in Grade 4 - just for this repertoire). Some say another piece - Chaconne in D is also a big deal - with more complex lines than BWV565, and I took about a year or so to master that (how come!!!)
