Impossible to answer a question like this but the ones that always impressed me most mechanically (at least consistently) were Extaz, LeBrave (not even a meme) and Drake tbh. It kinda makes sense since they all played/trained together so much.
I mean I trained with them a lot too, also with Maharbaal, but nothing brought me at a high level like them.
That was incredible to see how Haze knew all the mechanics of the game, I remember myself training with him. Multiple times he asked me to keep launching the same stab until he could do what he wanted to do with it. He analyzed all the mechanics and took notes.
It's a bit different with Extazz as his playstyle is way more classical (in duels), but also not classic at all in the same time. He always uses the same mechanics to kill you, and he always does the same thing continously, but at the end he wins. That's a bit like Hokej who was also all the time using the same mechanics.
At his highest level in 2015/2017, Haze was for me the most difficult person to face in 1v1.