Update: figured it out. Preferences>Display Settings>Display Sensors>Resolution: 1024X768 Works for my 20in monitor. You also have to re adjust your Kstars screen size using mouse. Is there anyway to stop Kstars from starting when you start the Rpi, would be nice if it were an option.
Just re imaged my Sd card 1.5.3 for my rpi4. started up the new os and the kstars program opens up but it is so wide, I can't minimize it like before, I also can move it right or left to get to the minimize window button. I there a way to unfreeze it to scale it to fix my 20 inch screen without having to go into the terminal and made modifications? That is as far as I can go to set up. all my settings are to wide. I tried to adjust the monitor screen size but no matter what screen size Kstars screen is too large.