Thanks for the feedback!
I will look into it, and try to replicate the issue, it should use main monitor's position and dimensions but for some reason it does not in this case.
Solution 2# would work, the game worked this way in early builds but we had to change it to allow Linux support (it handles windows differently and would not allow moving the window outside of display boundaries which basically prevented larger character size and ability to move around significantly) and yeah, also minigames and activities, especially planned ones.