Depending upon the countries you'll visit, a service like Roamless could be an inexpensive plan, and for text and calling, any iPhone from the past 6 years or so should have the proper bands for connections.

If you list the countries you might visit I can check my plan for service and per minute costs with Roamless. Their account balance never expires so whatever small amount you deposit is available until you need it in the future. In Estonia for instance, calls are charged at $.02-$.09 a minute, data at $.2.45 Gb. The Ukraine is $0.18-$0.34 a minute, data is pricey at $12.95 Gb however. Most Euro countries are pretty low, but as you can see, there are some that are expensive.

Edited to ask: I am unsure what you want when you say you wish to avoid Google and Apple devices. Does that mean no Android or Apple operating systems?