Graphics Settings likes to control itself

So, when I’m playing games on roblox like a normal guy, I start to lag a lot and I open my settings. I always put my graphics level on AUTOMATIC but sometimes it loves to change back to MANUAL which is very annoying and sometimes I can’t even switch it back because of how laggy my game is when it switches to manual.

Does automatic stand for automatically making me go mentally insane?

Help me please.