Have you ever noticed when you check your phone for the time, you check a whole lot of other things too?
At least, I would. Lemme just check this other thing real quick, I’d tell myself…. and then I’d look up, twenty minutes later.
Get a wrist watch* and a bedside alarm clock. The only notification they give you, is what time it is.
* Admittedly, ymmv if you prefer a smartwatch. Tried a Fitbit once, and it was terribly distracting for me. Finally decided that if an alarm clock succeeds in waking me up, I am fit enough.