I've found that just calling and texting is really insufficient these days in much of the world. At a minimum, WhatsApp is a very useful app that lots of people - and firms / institutions - use for messaging these days. E.g., traveling in India, many people, including cab drivers and such, are reluctant to text or call and only use WhatsApp. Also so many things today have information conveniently available on their web sites, e.g., opening hours for a museum, that's extremely inconvenient to retrieve (even if possible) via text messages, voice menus, or calling. This is all quite apart from the "convenience" aspect of simply being able to use online maps and directions, booking apps for trains or hotels, etc. Yeah, one could spend a lot of time on the phone during business hours to get all the information and make bookings, etc., and carry along paper maps, but at least to me it's unthinkable today to not travel with a smartphone with plenty of data access at all times. It's all doable, but just seems very awkward to me. Obviously, YMMV. Good luck! My only recommendation would be to sign up for at least a minimal data plan to be able to use a few apps like Google Maps, WhatsApp, and a browser like Chrome.

It is possible to get an Android phone and not sign in with a Google id, although it's tricky and not that easy. Alternatively you can sign in with a throwaway Google id that you don't care about.