Intel sold its XMM modem chipset business to Apple. It did not exit the wireless market. As you can see here, (from 2023, four years after the Apple sale,) Intel has been and continues developing new products for wireless operators, and is now, with this new Xeon, on its third generation of such devices. Overall, Intel exited the low margin, highly competitive "client" end of the wireless world and focused on the high margin wireless network operator end, where their VLSI capabilities face less competition.
Your take on Intel wireless is the result of consuming headlines without understanding. Your take on Xeon being exclusive to workstations, servers and supercomputers is similarly naïve. OEMs build proprietary systems based on Xeons such as this new 18A device and embed them in network core facilities that are not "datacenters." I wrote "essentially embedded" because, while the term "embedded" is not used to describe these deployments, that is essentially what they are: dedicated silicon deployed in proprietary systems that are not general purpose datacenters. They will not be running arbitrary VMs or other "public cloud" workloads, but instead vertically integrated software stacks proprietary to a wireless operator's business.
Please, in the future, consider your own ignorance before commenting: there is more going on in the world than what you're shown on Ars Technica and YouTube.