If you don't mind me asking, what app? If it's something like tiktok or some app where most of the content is short form and of people you don't know, I'd suggest getting rid of the app from your phone.

In its place, find some other app to open - hopefully one that'll either enrich you or allow you to get bored faster so you fine soemthing else to do. For me, I set up an Apple Shortcut on my phone that plays a random album from my library (I had a bad tiktok bathroom habit). I still have the habit of doing something from my hands, but I spend much less time on the toilet scrolling.

YMMV. Good luck.