Iphone 12 India data usage

I traveled to India for 4 weeks in September and October 2022, after reading this forum. I am back in the USA and here is my review. T Mobile free data on cellular networks of India worked almost everywhere during my 4000+ kilometer zig-zag drive journey in India, as I visited various historic sites and infrastructure projects to review in the field. Relying on T Mobile, I was able to get free Messages, WhatsApp, Email etc in Delhi including Delhi airport when I arrived, and thereafter in numerous small towns of Chhattisgarh, towns and cities of Madhya Pradesh including Bhopal airport, of Uttar Pradesh, small towns and cities of Odisha including Bhubaneswar airport, and most of West Bengal including Kolkata airport. Only exception were isolated parts of Raipur city and parts of Asansol city (may be one or two tower issues?). No bill surprise afterwards too, now that I have received and paid the monthly bill that covers the period of my travel. Slow speed data is indeed included free by T Mobile in India, and for me, it worked nicely in the states mentioned above when I tried relying exclusively on T Mobile service. For high speed data and apps such as Google Maps and Apple Maps, I used a portable JioFi. When JioFI battery was exhausted, and sometimes just to test, I relied on T Mobile exclusively. I was traveling with the recently released iPhone 14 Pro. I have the Magenta Unlimited plan. These were my phone options → Settings : Cellular → then Cellular Data : On (Green); Cellular Data Options : Roaming On; Personal Hotspot : Off. T-Mobile Turn On This Line : On (Green); Scrolled down and confirmed that all the desired Data-driven Apps were On (green). Sometimes I had to toggle the Airplane Mode on-off, or switch off then reboot the phone, to help re-login the phone with local cellular towers.