The things there is no longer a standalone antenna just for one technology, all the antennas handle multiple technologies and sometimes all at the same time. [br]
There are at least 4 cellular antennas on the Xs Max, as it supports 4x4 mimo downlink. The top and bottom ends of the rear case each contains 2 antennas for cellular, some of them are also shared with 2x2 mimo Wi-Fi 2.4G and 5G bands, GPS, Bluetooth and NFC.