Hey Personally, I recommend that you do what you want with your game, but yes, after the JAM, since they evaluate the game DURING the JAM, but if you want to update the game at the end of the JAM, to avoid breaking rules
The only thing i really want to change with my game (that would make it 2 handed) is to add aiming with the mouse instead of Auto-Aim.
I asked one of the moderators on the discord and they said:
"sure, you can do that. make sure your submission follows the limitation though. you could make web build one hand control and then include a downloadable with option to have classic controls"
after the jam ends, I'll make the non-jam controls the default one (that plays in browser)