Same thing happening with me. Since like December 14th (apparently with the release of iPadOS 16.2 I think) my iPad 8th generation (2 years old) literally went nuts. The upper part of the screen (if it's vertical) won’t respond to touch or if it does it does it after many attempts. I thought for a long time that it was my fault but then reading online I noticed that many have this issue. I did all of the things that they suggest online, so restarting it, rebooting it, turning off all of the AssistiveTouch settings (btw I think that AT is a part of this problem, too cause I was using it to turn up the volume since the button is broken), I even brought it to the nearest Apple Center and they asked me €300 to fix it, what???? That’s like more than half of the price that I bought it. Now it’s updated to iPadOS 16.3.1 but the problem is still here. Luckily I have my keyboard to type, otherwise I couldn’t even do that, since even the typing is broken. If I type on-screen for example the letter A, it will automatically type aaa 🫥 Wtf am I supposed to do? Oh I forgot to mention that I also have a pen (not the Apple Pencil) and sometimes the parts of the screen that my finger won’t touch will be activated by the pen. I’m ofc really mad cause I need my iPad to study and I can’t afford to buy another one rn.