International roaming / India - has issues

I traveled to India for 4 weeks in September and October 2022, after reading this forum. Given the mixed comments so far, I wondered "will the cellular data with T-Mobile work or not in India, and will there be surprise charges"? I am back and here is my review. Well, it 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. T-Mobile free data service driven Messages, WhatsApp etc worked in Delhi including Delhi airport, and 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. 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).