Voicemail problem on factory unlocked Note 10+

I recently purchased a Samsung factory unlocked (U1) Note 10+ to replace my XM S10+.  It's working just fine with the original SIM that I swapped over from my XM S10+.  VoLTE, WiFi calling, everything works.  Except....  Voicemail notifications.  None.  Zip, zero, nada.

The XM visual voicemail app does not work (nor on any XM purchased Note 10)

"the newest Samsung phones (Note10 included) are not compatible with the Xfinity Visual Voicemail app and moving forward, all new phones will be using the provided voicemail app (not the xfinity visual voicemail app) in which case on the note10 is audio only".

With the Samsung default voicemail app, I don't receive any notification that I have a voicemail message.  And if I open the app, it always says "no new voicemails".  But if I touch the "check voicemail" button in the app, my new voicemail messages are there and I can listen to them.  I've enabled all permissions for the app, and enabled all relevant notification settings.

I suspect that the problem is not related to app notification issues, but rather related to the app accessing/checking my voicemail.  Since it always says "you have no new messages", whether there are messages or not.

All feedback/suggestions welcome.