Did the anime cover all the manga up to Season 4 of Shingeki no Kyojn?
No, it does not. The anime is behind the manga by more than 30 chapters. 

The last episode of the latest Attack on Titan season adapted Chapter 90 of the manga so Season 4 would, presumably, start from Chapter 91.

It should also be worth noting that Season 4 is the last season for the anime series, given that the manga is already on its final arc.