My phone data is not working (apps not working) — neither cellular, nor WiFi. But I can Make phone calls and TXT.

Thanks for chiming in, didn't see your reply. Went to Genius Bar today. Left long-winded reply to the Xfinity employee who replied below. Baffled everyone.

ChrisXYZ thanks for sharing this experience and for letting us know the reinstallation fixed the issue. I'm glad the phone is working for you finally! 

It affected all apps, and the browser, but not TXT messaging, and not phone calls. I dealt with this for three days. I finally took it to the Apple Store this evening, and the "Genius Bar" was baffled too. What is even weirder, is that the identical thing happened to my iPad—both at the same time (around noon on Thursday), which would imply it was something to do with my Apple account, because my iPad is WiFi only. There was a newer version of the iOS. The iPad was easy. I updated the iOS, and the problem was fixed, but the iPhone? No dice. I spent several hours with ChatGPT. I tried doing the iOS update, but it would hang without a network connection. I tried the update connected to my Mac, but it would get ~50%, and hang. Left it running over night, Thursday, and by 11am Friday it had completed "preparing" the iPhone to update. Then could not run the install. The Mac also had a newer OS version available, so I updated my desktop machine. Then it looked like it was going to take. Completed the upload of the newest iOS, but froze up during setup. Again, the Genius Bar was baffled too. They ran a bunch of tests on it, including scanning for deeply embedded spyware (like Pegasus), and the hardware was given a 100% clean bill of health by all their diagnostics. So they wiped the phone and did a clean install of iOS. Now it's working, I'm just having to manually reinstall everything from scratch.