iPhone cannot access cellular data since upgrade to 17.4.1

It surely is not iOS 17.4.1 because...

I conducted a thorough search of this forum using the term 'Cellular network after iOS' or "Call Issue iOS" and uncovered numerous posts detailing similar issues across various iOS updates. This suggests that iOS updates may not consistently be the root cause. Below are a handful of examples extracted from over 6,000 search results:

"After iOS 17.4.1" will be an addition to this list posted by you.

Cellular Network issue After iOS update

• iOS 16.4.1 installed = Cellular Network Data Issues
• IOS 17.1.2 killed my cell service!?
• why is iPhone 6s has no cellular connection after ios 15 update?
• IOS 17.1.2 Update caused major cellular network problem
• Cellular network is not recognised after updating to IOS 16.
• Re: I don't have cellular service on my iPhone after iOS 15.7.9 update
• Loss of Cell Connectivity After IOS 16.3 Update- iPhone 13 Pro Max
• Cellular error no network available after iOS update 15.4
• Cellular Issue with IOS 14
• Re: No service (cellular network) after upgrade to 14.7.1

Call Issue after iOS update

• Re: iOS 16.6.1 telephone call issues
• Upgrading to iOS 15.6.1 call failure on my outgoing calls using cellular but callsconnect when using WiFi calling...
• My iPhone failing calls after the iOS 16.5 update
• Calling Issues after iOS 17.1.1 Update
• I have calling problem after update iOS 12
• IOS 12.1.4 CALLS PROBLEM
• Re: iOS 16.6.1 telephone call issues
• iOS 11.0.3 Call and Sound Problem

It's possible there's a known issue with your device

It's not always the iOS update's fault!  Many things can cause phone problems.  If you tell people you think it's an iOS update, it might make it harder to fix or find a solution for the real issue.

Remember, the right question often leads to the solution!

iOS updates aim to enhance user experience, boost security, and fix bugs rather than disrupt core features. The majority of the issues after updates might stem from underlying, unmentioned factors. Updates won't typically alter personal data but may refine settings or features. Backup before major updates for safety. Review Apple's update details and backup advice for a smooth process.

Kindly consider checking your settings and addressing any device issues before attributing the issue to external factors. This could be a pure coincidence that the iOS update affected the iPhone functions.

Before initiating a standard iOS update, it's advisable to create a backup. Have you completed this step? If yes, proceed with the restoration from the backup.

See what each update does: About iOS 17 Updates, About iOS 16 Updates, About iOS 15 Updates, About iOS 14 Updates, About iOS 13 Updates, About iOS 12 Updates, and so on...