Here some YouTube videos - one on e and one on Ubuntu Touch and a really cool hardware phone device:

Android without Google: the /e/ Project blew me away!

Ubuntu Touch + LineageOS? THIS Is The Linux Phone I Want!

Consider using ting as for phone/messaging/data-plan service

Ting has an approach where you use their planner to figure out a plan that would typify your monthly use - that establishes your monthly baseline bill - if you exceed that plan's quotas, you'll be charged for that additional usage. (Perhaps you need to reconfigure your baseline monthly plan - say you're really using more like 4GB instead of just 2GB on your data plan). They also allow for buying a minimal plan just to keep a phone active for potential use - at about $5 per month. Can then have extra phones laying around - say a phone that is just for the baby sitter to use when she comes over.

Also might want to youtube search on the PinePhone and the Librem phone. The PinePhone has a number of phone OS (based on Linux) to chose and try out - really easy to do because it can boot them off of an inserted SD card. The PinePhone is about $150 - it's aimed at kind of an early adopter and beta test sort of audience as it's a community effort that is trying to work toward a kind of 1.0 product definition.

[edit] I made this posting too for those that want to diversify their communications options still further: get GMRS radio gear as some alternative comms for any coming comm blackouts