You could get any Wi-Fi enabled camera, something like a ring or something way cheaper. Place a small but reasonable sign at the end of your driveway indicating that it is a private drive or there is no public parking.

Once you have done both of those things, you just need to contact the parking app and try to register your address. When there is a conflict, I am reasonably confident you can prove that you live there. If anyone parks there again while you are out of town, you will see it on your cameras and you could have them towed. In most states, you can have someone towed from your private property without any legal liability. Putting the sign at the end of your driveway just reinforces this. The bonus with the cameras is that if your neighbor decides to remove or obscure the signs it does not make you liable and you would have them on camera doing so.

Also, because this is UL PT, I would also suggest getting your hands on a large amount of Windex or ideally the Windex outdoor concentrate, freezing this into discs, and tossing these onto his roof, it is bushes, or otherwise around the property as close to the house as possible. Then, use things like local PD Facebook pages to anonymously report your neighbor is acting erratically, often exhibiting paranoid or violent tendencies, and their house smells like Windex. You just described a meth addict. Most likely, they won't find anything, but if there are consistent complaints and the house really does smell like Windex when they show up, they are very likely to have a long conversation with him that could be very embarrassing.