The base game has five jump buttons: Z, Space, Left Shift, Right Shift, & Ctrl. I personally see no issue with binding 2 or 3 buttons. Really, you could bind an arbitrarily high amount of buttons and see no significant gain compared to 2 buttons due to how inputs work; anything above 2 buttons will give basically no benefit since the game waits for a key release (even if its a different button) before allowing another input.

(Also, having looked at the code, I can 100% confirm that a zip with a controller is impossible. AA forgot to add a line of code into the controller script that is responsible for zips that is normally present in the keyboard script).

harry is in the discord under the name of "hr", you could ask him if youd like