Fixed bolts not detachable!!

Hello, I’m busy at the moment removing my license plate holder from the rear of my pajero. Now I have the problem that the two screws are rusted so hard that I can get them off with nothing. Yesterday I put WD-40 on it, nothing. Today with grease grease, nothing. Screwdriver and battery still and still used, nothing. Now the problem is that it’s really emptied out. Do you have any idea how to solve the screws best without breaking the tailgate? b the screws break doesn’t matter, there’s nothing left anyway. P.S. the reason why I take them off? Just looks better. I thank you for your tips.