The product work is higher level system packaging, such as antennas and application-level manipulation of the whole RF block. But since so much is digital now, that is more software/computer architecture work rather than RF. The COTS RF circuit itself may have standardized serial or even packet interfaces to the rest of the product.
If you are budget constrained then you just design your signal chain in discretes like everyone else.
Lots of RF devices doesn't actually mean much RF engineering.
If you want 5G connectivity almost everyone buys an integrated module. Chip, antenna, and certifications included. No serious RF engineering required, no RF engineer in the building.
Those modules designers would be purchasing their chip from one of a few companies, like Qualcomm or MediaTek. Even then most of the work isn't RF engineering, it's stitching together a product and grinding through the certifications.
Much of the innovation is done away from the consumer space where certifications are less constraining.
Theres the whole thing where all the wigig chips that dell binned got upcycled into a companies flagship rf product.
Cambium v Ubiquiti has been an ongoing contest. Add Mikrotik in for good measure.
RF Elements is always trying to sell me something new.
Aviat has bought out NEC's famous flagship RF line, at least in terms of US distribution.
Theres enough happening.
Mil systems have severely constrained supply chain limitations too, while consumer vehicle systems can comfortably be produced in their millions from China.
Mil is huge