I've been working on an Accessibility Suite for Godot that addresses some of the points mentioned in this thread; a custom is_action_just_pressed function includes a customizable delay, so a player with hand tremors who might accidentally press the same button multiple times in a short time period will only register as the one original intended press. There's also functionality to convert button holds to toggles; so if your game normally requires players hold down a button/key to crouch, for example, you can easily surface an option to allow players to press the button once to crouch, and a second time to stop crouching. If any Godot devs are participating in this jam, hopefully one of them can find this useful!
I don't think I'll have time to participate in this jam, but I'll definitely be monitoring it to learn what other ways us developers can work to make games more accessible for everyone.