Kjgraph
Maybe it's your external keyboard, don't know if you connect this each time, but if the keyboard got wet or lemonade got into it, it will cause ghost inputs.
I doubt someone is attacking you, because it's obvious that whoever would want to attack a device would not do this in a way that the user gets aware that something is going on- and ghost input and moving screen content is something a user will notice for sure.
It's very likely a hardware problem, the Pixels aren't great on the hardware side, they are a typical Google product where some parts are good, and the most parts at best average, as you can see in the recurring huge battery problems that are present in many device generations since years.