The old muscle memory only required sliding along the bottom edge for a given distance then pressing the lower part of the screen.So you need new muscle memory to swipe up and tap a button
I tried to "practice" a new repeatable routine for the defogger but I couldn't do it predictably: slide along the bottom edge to a (different-than-before) place, slide up, return thumb back to edge, stretch index finger, rotate hand using thumb tip (at the screen edge) as the pivot point until index finger is vertical, then hit the screen. More than half of the time I missed it, and for the rest, it was a random draw between front and rear defrost buttons.
Needless to say, no driver should have to deal with such a complex process while driving to accomplish a very basic function of blowing the windshield.