Link please? Where is this confirmation?
Also, this is concerning the rog Phone 2, not the Zenfone. I don't know why she mentions the Zenphones, I never said anything about those in my support email. You would think Asus Flagship series (ROG) would get a little bit of LOVE, like, not get turned into expensive bricks less than 2 years after their release!
No, it most definitely has NOT always worked. This is just not a "it works for some people sometimes" kind of thing, it's a hard limit of the protocols. You cannot do 4G data and 4G voice at the same time without VoLTE.
Support for t mobile volte was already added in android 11 beta
It was added in A11 beta for Zenfone 6
Considering rog 2 was launched in the same year it should get it with a11 beta too hopefully