"Beautify this slide" is a cancer.
I've used Slides regularly for over a decade. No change or new feature has bothered me more than "Beautify this slide" popping up over and over. It changes the frame size, and moves everything. Plus, when I'm in the middle of changing or editing something and it pops up and everything shifts, it makes me think I did something. I really f***s up my work flow.
It's like the worst pop-up ad. And it does it constantly. I've started filling out a "Help Improve Google Slides" forms when it happens. I've probably sent dozens by now. I hate it so much, I've started training myself on PowerPoint (which I hate even more, but might have to get used to).