I got my wife the xs and the max for me and we both noticed far worse reception on T-Mobile in los angeles.
I decided to take both new phones with me to work for few days, I travel around the city alot and compare to my 2017 iphone x.
I’ve done over ten tests in different locations, put the same sim in the 2 new iPhones and in my old x and in Every single text, the iphone x had double the download and upload speeds then the new iPhones , and in the some areas, the X had one bar reception where the new iPhones didn’t have any signal.
Has the same results on wifi.
I then went to apple, told them about the issues, returned both phones and got another xs to test. Exact same results, so returned it too.
We’re both keeping the iPhones x , this years iPhones have terrible cellular snd wifi reception and coverage. If you need a phone that actually works well as a phone, Stay away !!!