I just purchased an iPhone 11 to replace a Samsung S8 which had a working hotspot / tethering option. On the iPhone settings menu, there is a popup which directs you to Xfinity mobile support web page, basically a dead link.
Initially I thought this was related to just swapping my old SIM card into the iPhone and not formally activating the new SIM. So I did activate the new SIM, but same results.
Tethering, etc is very important to me for those occasions when access points are offline or otherwise not accessible.