I was just thinking about Cal too. I listened[1] to Deep Work and Digital Minimalism a couple years ago and still use many of his prescriptions. Namely, I have no social media or gaming apps installed on my phone. On my home screen for quick access I only have Google Voice, Messenger, Maps, and the camera app. The browser app (Firefox with uBlock Origin extension) is buried and it deletes everything when I close it, so there's no history, bookmarks, logins, etc. to make browsing more streamlined. I often leave the phone at home or in my car when I go out. I leave it by the front door when I'm at home instead of keeping it in my hand or pocket.

I find that having a very light data plan helps too (in addition to saving money). I have the $5/month annual plan from Red Pocket that gives me 500 MB. I'm well aware that I could burn through 500 MB very quickly, so that makes me think twice about whether I really need to load a web page if I'm out somewhere without Wi-Fi.

[1] Audiobooks on my phone, ironically. But making audiobooks more accessible is probably the best value that smartphones have provided for me. Libby, for borrowing audiobooks from the library and listening to them, is the one entertainment app that I have installed.