Turn off imessages on ipad

How do I turn off imessages from my ipad and also not allow anyone to turn it back on without signing in with my apple id password? I used to be able to do it in the old OS but not on the new one...I share my ipad with family but don’t want them snooping through my messages.

i tried not allowing the messages app in the screen time settings but it doesn’t work because it doesn’t ask for password so anyone can modify my screen time settings. It’s really weird!