New User - Question about Display Settings

I just downloaded Retroarch and am in the process of getting things squared and set up. Right now I’m trying to figure out if there’s a way to keep the screen settings universal across all platforms. If I set the menu to display full screen, then it will go into windowed mode when I start a game. it will go back into windowed mode at a smaller resolution (especially if it’s a handheld system emulator). If I resize the window, it then changes to a really small font if I try to exit out to the menu. When I loaded up an N64 game, the menu window became really large. It also seemingly deleted the menu wallpaper I used and went back to the default background. Is there a way to quickly and easily make everything run at the same resolution (preferably defaulting to full screen for all the cores)

Just setting it to fullscreen mode in video settings should work. If you do that before loading a core and game, then quit, it should write video_fullscreen = true to your retroarch.cfg and use fullscreen mode as the default for all cores.

Thank you, I think I have it working now. Not sure if this helped, but I also set the default aspect ratio to 4:3 and it seems to have applied to all the cores I’m currently using