Based on members in this community and personal research, it appears Samsung is keeping the code for enabling VoLTE secret. In the US now, all the major cellular networks have switched over to VoLTE. So all the Samsung e/os owners cannot use their device.
If there is anyone out there who has found a work around, I would love to know. My research hasn’t yielded any results.
Also, if you only add the warning to the Samsung specific pages, there might be people who miss it.