Open Legend is very malleable but changes to the fundamentals of the game, like this one, would require a total rework, resulting essentially in a new system. Pathfinder needed a new edition for their Action Point system to stick and be successful but I’d say that’s because they kept their system really simple. Your outline already looks more complicated than the PF2 system, so my advice is to keep it simple. You could go really granular with such a system but that works much better for video games because the game does all the bookkeeping.