Apple uses Qualcomm as well for their 4G/5G modem. They've started work on fixing that (by buying Intel's business unit that was working on that in 2019) but iphones still contain Qualcomm modems for now.
Most of the industry, except some Chinese vendors, use Qualcomm technology. There just are not a lot of 4G and 5G implementations out there.
In most markets, you end up licensing their patents regardless of whether you use their hard and software too. They have a near monopoly because building a replacement is a non trivial exercise and even if you succeed, you'll still have to license the patents. So, even when Apple ships their replacement, they'll be licensing patents from the likes of Nokia, Qualcomm and a few others for quite some time.
https://www.bloomberg.com/news/articles/2020-12-10/apple-sta...