Fullscreen lag

hi, before 2018, my pc never lagged when i passing from normal mode to fullscreen mode in adobe premiere. but suddeny it started to lag when i do this. everytime i hit the shorcut for toggle fullscreen program freezes at least a few seconds and same when i exit from the fullscreen. i have to wait like 5-6 seconds to play the video. also it looked like monitor screen gets refleshing like it does when you change the desktop resoultion.

like i said before 2018 it wasnt a case so what can i do? is this universeal problem or just for me?