It's the antenna, not the modem. FCC already shown that in their tests. WiWavelength posted the first article on the 12th prior to release of the new phones, and no one paid attention. The second is his followup. Without a doubt, Apple will blame the carriers and ignore us.
https://www.wiwavelength.com/2018/09/iphone-xs-and-xs-max-mostly-fail-to.html
https://www.wiwavelength.com/2018/09/antennagate-reduxs-if-so-what-can-apple.html
https://www.wiwavelength.com/2018/09/iphone-xs-and-xs-max-mostly-fail-to.html
https://www.wiwavelength.com/2018/09/antennagate-reduxs-if-so-what-can-apple.html