Im having the same issue. If I send a email from hotmail/outlook to my verizon number ******@vtext.com or ******@vxwpix.com I do not receive the message on my verizon iphone 15. I get no error message about the message not being deliverable and I am sending a one word email so it is also not a length issue.
As a test I sent an email from outlook to @vztext.com and I received a non deliverable message from outlook so at least I know that if I were sending my emails to the wrong address for verizon I would get an error response.
I can however receive messages on outlook sent from my verizon iphone 15 message app. The email says it was sent from xxxxxxxxxx@vxwpixcom. I then tried to reply to the message I received but the reply did not get to my iphone. I think the problem is with verizon at this point but I am not sure. One the phone with Verizon now, but if you know a solution please let me know.