In Diablo 3 you continue with paragon levels.
I will say that even that starts to get harder to see gains. Somewhere around 2000-2500 you have to do a lot to see a gain of 1 level or be super geared to do very hard content. For most players, they won’t hit that high in a season, so it is fine.
I wish we had something like that in D4.
I also wish glyphs that go across classes were account bound so we wouldn’t have to level the same one more than once a season - like D3 gems were not character bound but account bound.