Wanted to add my experience.
I had this problem for three months and may have fixed it.
I am on Visible, seems to work the same as Verizon.
I turned off WiFi since it seemed more people got verified using cellular data.
I uninstalled current Messages version.
Installed version: messages.android_20220131_05_RC00.phone.opebeta_dynamic
Opened, gave network permission, set as default, opted into RCS I think they called it dynamic messaging.
After that I got the standard "connecting" in the RCS menu. It would either sit on "connecting" or "trying to verify" for weeks regardless of what version I tried.
Sidenote: xyzzy debug enabler would immediately disable in this version.
Went to App Info menu for Messages, clicked 'force stop', went back to Messages and my number was now verified and connected, for the first time in months.
Upgraded through store to latest version, and I am still verified.
I should mention, I tried almost every method available before this. So I am surprised my simple method worked. I tried the debug menu tricks but could never get a version installed that would give me the ACS menu to manually insert a link for my carrier to activate RCS.
It has now been three days, I'll keep my eye on it.