So here is what I finally figured out. I hope this helps. My iPad began having trouble after the 13.4.1 update.
The update itself is fine, however app updates from the App Store were not fine. After days of my iPad locking up, black screens with lines through it, iPad so frozen I could not initiate a hard boot... all of these troubles were the result of app(s) updates not downloading completely.
I deleted every app that was having trouble and rebooted a final time. I have not had trouble since. I don’t know why apps are updated automatically now. At least I am not able to find the previously available option to update apps manually anywhere in the App Store.
All told I had at least 8 apps that were attempting (repeatedly I have no doubt) to update. So, go look for any app with the down arrow next to it and either down load or delete. You can always re-download it provided it’s still available.
Then reboot. Good Luck