Trail cameras are going to be the absolute worst way to prevent trespassing. By definition they are hard to see, so unless you put one square on a gate, chances are they will never be seen.
If you are having an issue with a neighbor, talking to them is the only way forward. They might be mistaken on the borders, or some other issue. If it is some hunters, especially if you are butted up to public land, it’s probably just because they can’t tell where the property line is. There’s nothing better than bright colored no hunting signs for that.