I have a French Orange SIM and use their Mobicarte system (30 euros for unlimited voice+text & 30 GB, over a 30 day period) Works in France and most European countries.

​​​​My phone is a Galaxy S20 ultra. I've never had network compatibility problems and I have travelled quite a bit over the years. Back in the days, lots of NA phones were CDMA instead of GSM (i.e. everywhere else). So the trick was to subscribe to a gsm provider.

​​​​​[EDIT] you refer to the eink Hisense A5. I've dropped using it because autonomy was simply not worth the trouble. I carry an eink tablet, somewhat similar to a kindle that runs recent Android. Good autonomy, excellent device to read and edit documents synced to Drive. [/EDIT]