I think lean should be much more faster, and should tilt your screen, like in the GIF below (Escape From Tarkov Leaning GIF)
It feels very slow sluggish and somewhat clunky to lean, and in 1PP it doesn't feel good. It looks kind of disconnected, and robotic a bit too (only top part of body moves, but maybe it's a good thing, just looks and feels weird.)

Tilting screen when leaning also feels so much better, and actually feels like you're leaning (immersion)
Showcased in the GIF below, it's from EFT and they do leaning fairly well :)