Hi, I would like to A) not be able to pick up my phone and waste time but B) still get important messages

To achieve A, I could turn off the phone but this doesn’t work for B. I’m looking for a function a bit like those computer apps where you have to put in an insanely long code to access the web.

I know there are apps like Freedom, which prevent access to Reddit, Facebook, the browser, etc. for a specified length of time but I still want to to access them if I have to.

Any ideas? Thanks you.