DIsable AR Camera (Unity)

Hello, So I have started using Vuforia in the last couple of weeks. I am using UNITY

So, I run my app and at start vuforia is not initialized and the app is not laggy, then i press a button i created to initialized the camera and i do my stuff there

and after i come back to my scene after i set the videobackground of vuforia to be disabled... i get tons of lags.. I think it is because i didnt deinit the camera tho i cant find any way to do it..

i might be stupid but help a fellow here :)