Unfortunately due to how pixel art works it's pretty difficult to set up something like maximized window without distorting the entire art. The only thing I can think of is adjusting the base viewport, but that could easily mess up gameplay by showing more/less than you should see
Yeah i totally understand as someone who is learning pixel art, stuff like this has to be made accounted for in the begining otherwise you become limited by stuff like this, I still enjoyed the game nonetheless!