The information published by the analyst includes a sourcing list of all the semiconductor content of the smartphone; one conclusion of the teardown is that, “[the] AMOLED screen and TrueDepth sensing are key hardware differentiators in [the] most expensive smartphone to date.”
The overview of the teardown comments that, “The assembly and testing of the TrueDepth system and its individual components is challenging and likely a factor in the production delays,” adding, “For instance, the assemblage and test of the Texas Instruments and ST Microelectronics subsystem for the flood illuminator is far from trivial and requires a high number of test equipment pieces.”
Far-from-trivial could equally be applied to many other aspects of the construction; for example, the main PCB and RF/interface PCBs are interconnected into a single assembly by an interposer/soldered via peripheral ring ( see images reproduced below, source IHS Markit ). The design also fits maximum battery capacity around the disparate sub-systems in the design by employing two separate cell assemblies.
IHS Markit; report here