Phone calls drops + wi-fi issue on Iphone XS max

I have had the problem for a month and went back to my old X. People keep posting to turn off LTE and someone marked it as an answer. Disabling functionality is not a solution to the problem and at best is a sort-of work around although it still doesn't eliminate all dropped calls. After Apple loaded some logging profiles and collecting data, what they confirmed is that I dropped many calls, as much as 15 times in a half hour. Hardware tests looked like all worked fine. Dropped calls were particularly bad if I was driving around an it appeared the phone could not make the handoff to the new tower. Apple agreed to replace the phone last night, on them, and not using my Apple Care. I drove around tonight and made a call from my new phone to an old 6S Plus. Went all over the city with the phones connected for more than 2 hours without dropping a call. It appears the phone swap resolved the dropped call issue. I saw someone else say they swapped the phone and walked out of Apple and had the new phone drop calls. I suspect either a bad batch of the new Intel cellular modems or maybe just poor quality control whereby bad chips get out sporadically and are not limited to a particular batch. Maybe something in the rest of the phone and not the modem however until Apple takes some of the bad phones and stress tests them to figure a root cause, we may never know and they may not want to publicize it. Ask Apple for a new phone. I responded back to the Apple tech tonight to let him know of my results. They need to end the pain quickly for customers that have spent a small fortune on a new phone.