High Cellular data use and Reset Network Settings - connected?

iPhone 16e, iOS 18.

Everything works fine, then the internet stops connecting via cellular data. Nothing seems to fix that. Was told by my carrier (Xfinity Mobile) to reset network settings. That reset (while not connected to WiFi) got the internet going, but I then noticed that day a ~1Gb use of System Services on the Cellar Data tab. I reset the cellular data stats and there was no drain on cellular data use (~10-20Mb/day) during normal phone use. About two weeks later I had the same cellular internet failure and did a reset network settings. Once again a ~1+Gb usage on system services.

Has anyone else seen this behavior?

Does a reset network settings use this kind of data? Maybe some download as a part of the reset?

Of course, if the internet didn't stop working periodically, this wouldn't be an issue. Any ideas on helping that out?