not receiving SMS texts. iPhone xs Max

SMS is a carrier feature. Contact your carrier.

See this article for additional information:

If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support

Doing a factory reset is the final troubleshooting step, not the first.

The problem might be because you restored your iPhone XS Max from a previous backup. You need to factory reset it and set it up as new. See the link below:

https://allthings.how/cant-send-or-receive-sms-text-messages-on-iphone-xs-and-xs -max-try-these-fixes/