Thank you for playing!
Yeah normally the UI should scale with your system scale but it's currently bugged and to be honest I postponed the fix since I plan to completely redo the UI system anyway. If I'm to submit to another DD before the redo, then I'll find a way to fix the UI scale.
I didn't expect people would like to move the camera using the mouse, thanks for the suggestion, I'll keep it in mind for later. Currently the Undo button doesn't work for objects or roofs and there might still be some bugs lurking in it too.
Making an engine is the easy part of gamedev, the hard part is making the game haha.
Thank you!