The different and competing interests in the implementation of 5G can be difficult to understand. Hopefully this article will answer most of your questions.
You don’t even need an FCC license to start your own 5G cell phone company. Just buy the equipment, hook it up, turn it on, and you’re a cell phone operator.
Information about big phone SoC chip providers
https://www.ericsson.com/en/blog/north-america/2020/cbrs-primer