That doesn't sound like a screen refresh rate issue. If it were, it wouldn't drag out like that. It would simply be jumpy. This sounds more like a software issue, where a bug has caused a substantial enough drain on resources that things don't respond in a timely fashion. I know you already reset, but it's possible something reinstalled during the next setup that actually carried the bug. I would first try to start in safe mode.
https://www.hardreset.info/devices/o...-5t/safe-mode/
If the problem goes away, then we know it's something you installed. If it remains, that means it's something from the manufacturer (hardware or software).
You'll need to register to be able to reply, but that will let us keep the conversation going and try to figure this out. For the video, I'd suggest uploading it to YouTube and linking it here (a moderator may need to approve it due to being a new account, so bear with us if it doesn't post right away).