Dynamically change main modifier

I want to dynamically change/toggle my main modifier from alt to super as some applications require alt as an input.

On my old config I've set up an empty submap to unbind all keybinds, however this was always clunky.
I'm not to versed with submaps and I'm still figuring out the new lua config options.
Is my best option really to duplicate every bind in a submap, or am I missing an obvious solution?