Does Square remind you of Cable TV. Like, back when it was clearly antiquated but everyone was still just giving them their money? We give them 2.6% and it is a struggle to do so. Please take my F'n 2.6%. I'll give you more 2.6%'s if you just make it easier to do so. Why can I not modify that basic form "additional info" and change the title of it and mandate a customer answer it AND/OR make additional fields. When this is over. It wasn't me. It was you all along.
So while I understand your struggles it's best to objectively ask for Feature Requests by telling Square what you want and why it will help your business.
I'm guessing you want to make the checkout comments section mandatory? What are you looking to accomplish with the change?
Square has been more receptive to ideas than most large POS companies, most don't even have customer support in any real meaningful way.
Best of luck and as usual I urge you to understand software isn't as malleable as you'd think, most software updates require months if not years of effort to ensure the finished product doesn't break. (and even then the best planned update can have bugs/glitches that aren't caught in the wild)
Putting in feature requests is as a game of patience and getting them to understand why you need a feature/implementation.