Whenever I have the resolution set to higher than something like 600x600 part of the game disappears off the top of the screen. I can almost play in 1280x720 in windowed mode, but a small part of the top is still missing, I have to hide the Windows taskbar or it gets in the way, and the mouse isn't actually pointing where it says it is. When I try to go fullscreen it is much worse. Setting it to full 1920x1080 in fullscreen cuts off the majority of the game, only showing the upper left corner. 720p is no better.

I have tried changing the resolution/fullscreen in the game options, chat commands, and the default file to no avail. Any fixes?

Try playing in fullscreen with the resolution of your monitor set as the in game resolution.