It seems like you're experiencing issues with iMessage and FaceTime, and it might not necessarily be related to an iOS update. Have you attempted to utilize your Apple ID to send messages or initiate FaceTime calls? This alternative approach is worth considering, as it operates independently of your phone number. Unlike using your phone number, which may require a distinct activation process, using your Apple ID can often bypass such complications. Exploring this avenue might just resolve the troubles you're facing with iMessage and FaceTime.
To activate iMessage and FaceTime using your Phone number
- First, check to know whether you have an SMS plan enabled for at least One SMS*** with your carrier. Contact your Carrier (Cellular Service Provider) the agency that issued the SIM to you
- If your iPhone is used with a carrier not found in the wireless carrier articles, make sure you can send and receive international SMS. (One international SMS*** Only)
- If you can't turn on or sign in to iMessage or FaceTime - Apple ...
*** You may not have an SMS plan (Domestic & International) enabled by your carrier for the SIM/eSIM that you use on your device. Apple Inc does not provide SMS services.