It becomes the issue of the thinking speed. Once I know what I want to say, the words are essentially already on the screen, but that can take a while.
I’m right-handed, but I have small hands that make it very difficult to type one-handed either way.
I actually did try to train myself to be ambidextrous as a kid, and it somewhat helped, but I never really stuck to it, so my handwriting is only passable at best with my left hand. I’d still probably be able to cope okay if I broke my right wrist or something.