IMessage and FaceTime Activation Error

I’ve tried everything imaginable to get IMessage and FaceTime to activate with my Iphone 13 Pro Max phone number, which was ported over from a different carrier. Everything works except IMessage, I get a message there is an Activation Error and then it defaults to using my Apple ID rather than my phone number. I’ve reset the network 3 times, turned off all of my other devices that use the same Apple ID, turned off and on the messenger app several times, checked the cellular network, Wi-Fi network and ultimately wiped out everything I transferred to my new phone and started over, downloading from the cloud. I get the same message. I’ve followed all of the steps Apple Support gives 3 times. Interestingly enough, when I reviewed what was available under my cellular data, the Message app isn’t on the list but FaceTime is.

what gives? Thanks!