According to Digitimes, Apple has increased the number of its suppliers for 5G-related hardware and that’s because it expects to deliver more mmWave-capable phones with the iPhone 13 generation.
The iPhone 12 family is the first lineup to support 5G connectivity but the mmWave support is limited to US as the rest of the world got only sub-6GHz 5G support. Now more markets are expected to adopt the faster mmWave standard and Apple wants to be ready.
Source