I find it interesting that typing "requires" both hands to press keys while handwriting "requires" only a single hand to write (and the other hand typically just holds the paper steady).

I think it would be interesting to compare hand dominance in writing vs typing then.

FWIW people using their phone as their main computer tend to type crazy fast even with one hand.

I always wondered if they'd benefit from a bridge app that would feed the phone's input into to their desktop/laptop, like a networked keyboard

Qwerty has a strong left-hand bias even if you're right-handed.