I'm fairly certain the problems you're running into have to do with the animations. For me, I got around that issue on my experimental builds by tying animations solely to the animationplayer and animationtree nodes, also by specifying an animationstatemachine. All other things, i.e. input and movement were used by its own state machine. To be honest though, I've been just using state machines for enemy controllers, as I find that characterbody2d is just too dynamic.
Also I know it's WIP but the E to jump and Space to attack was NOT doing it for me LOL