It’s awful.
During the first half of the tutorial series they make it work with multiplayer, but the movement itself is far from correct in terms of physics. The multiplayer support also would break as soon as some ping and packet loss is introduced. The tutor follows a lot of dumb practices, for instance, creating interfaces to avoid one single cast for ABP, most likely following a false excuse “Casts are expensive”.
Throughout the second half they scrap the implemented movement in the first half that works in a way in multiplayer, and simulate it using a hidden sphere, which doesn’t work in multiplayer by any means. In fact, they call SetActorLocation and SetActorRotation every tick locally, and call AddForce on user input locally, i.e. the sphere is never affected by the inputs on remote machines.
It’s one of the worst tutorial series I have ever seen.