Hello,
Thank you for trying my asset!
Whenever you change any of the CRT object's settings at runtime, you'll need to have it call the function "update_uniforms()" to see the changes reflected in-game.
To disable the effect at runtime, If deleting the CRT object causes issues, you could also choose to disable it by setting its "shader" variable to shd_raw. This shader is more or less a passthrough shader that only handles aspect ratio and optionally curvature (which you could disable for a raw pixel art look).
I hope this helps!