You could consider to not have a SIM card. No online connectivity and telephone that is.
All software you want could be loaded via WLAN. Camera, navigation (offline map database preinstalled, non-Google Maps), chess, music: all available still. Just no mobile internet outside your home, no monile telephone.
In fact I am seriously considering this for myself. I have my old phone, kind of broken phone in this mode - and have that with me more often than my new, active one
. I find mobile telephoning annoying, especially when being called. And I do not need mobile internet connectivity. Both imo get hopelessly overestimated - and of course hyped by political and business circles.
When I am not at home, i am unavailable, full stop. The telephone answering machine is on, use it to leave a request for calling back, or leave me alone, period.
Serious. I think it pleases some narcissistic needs of people to think they must, everywhere, all the time, be available to all the world, around the clock, no matter where. "I'm very important, the show cannot run without me", that means.