I'll provide a video that explains it.
Basically, there's a part of the game's code where WASD (and the arrow keys) have something attached to it, which Windows calls "Stick 1".
The Space bar has something attached to it called "Button 1".
Huh! Thanks for the (really nicely made!) video. That does explain what you're experiencing, but it does not explain why things are mapped this way. Crownbreakers is built in Unity and uses the Unity Input System. I don't do any controller mapping myself so it is weird that this happens. I'll do some more investigation but if you want to help figure this out, please jump on the discord!