My iPhone is saying no sim

Look here -

If you see 'invalid SIM' or 'no SIM' on your iPhone or iPad - Apple Support

That Apple Support article does not address all the issues. I had this problem on my iPhone 13, which is a dual SIM phone (physical and eSIM capable). I had to contact my carrier (vial my land line since my cell phone would not work). The fix involved removing the physical SIM, putting the empty SIM tray back in the phone, and then with the phone on WiFi, the carrier walked me through activating the eSIM.

Apparently this issue has been happening with multiple carriers after the roll out of iOS 16.