For the past year or so I've been mostly offline two days a week and even on other days only really use the phone for Organic Maps (npub1t2q…n4vh), taking pictures and Signal for comms, but if needed can (have to) switch to SMS. Every other app has mobile data turned off by default[1], which also allows me to stay on the cheapest data plan and increased battery life. It was "hard" in the beginning, but really not for very long at all and I think it quickly helped me deepening my sense of the "Big Here"[1], being more present in the moment/place/experience. It's also a very positive subliminal feeling, knowing I'm leaving a lot less direct data traces whilst out and about...
[1] Sometimes need to temporarily switch to online maps for realtime traffic info/detours, but only doing this very rarely...
[2] https://longnow.org/ideas/the-big-here-and-long-now/