Thanks for the feedback, especially the technical issues. I'm hoping Godot 4 solves the web issue.
Ah, yes, the dreaded muscle memory wreaking havoc when playing a game with different controls. I feel your pain. Anyway, I just checked my code, and jump is prioritized. If you're already in the look state though of course jump is going to fail. This is by design.
Window size and fullscreen setting, along with other things like volume control, will be possible to change when the options menu is added.