Apple Watch default input, is at the very least, terribly done.
If you've ever desperately typed "how change default from scribble to keyboard apple watch" into anything, do I have a solution for you:
If you turn
iPhone > General > Keyboard > Slide to Type
off, scribble is no longer the default way to type on your Apple Watch. You will now have to enjoy notifications on your Phone that prompt you to type there instead, but c'est la vie.