It's a UI problem not an hardware one imo. Pretty much when iPhone came out UI research flattened and everything seems so standardized now, I only see gimmick stuff like liquid glass. For example, I don't see why a submit button cannot float near the thumb on the right or left side of the bottom of the device(could predict by checking device orientation)

I cannot totally agree. From my experience, if the phone is wider than ~68mm, I cannot hold it firmly in my hand and operate it. The UI comes after that, for how far I can reach.