My *AF button started sticking 2 days ago. I could see a thin build up of gunk around the body of the button that goes inside the body. I used some floss to scrape up and out what I could see, then a very very mild cleaner or water (distilled is best) on the tip of a q tip to get the rest, and it's back to normal. I will say my Sony buttons on my A1 and even a7rv don't feel as springy as my canon buttons did and stick more 🤷
I'm not surprised by the screen issue. They don't feel very durable to me. I'll keep an eye out on mine as that's where my nose and cheek put a lot of pressure on the screen at times. Really wish we could have flipped the screen over to protect it! Sorry, that stinks!