How to enable VoIP or VOLTE on Sony Xperia 5

[AleksKhaos]

Hello Sony fans,

How to enable VoIP or VOLTE on Sony Xperia 5?

[Marino.Manolo]

How do I enable VoLTE?

https://www.sony.ie/electronics/support/articles/SX669701

[nikosEuP]

This article covers the case when the VoLTe related switch appears in the device menu. What about when it is not appear (the device does not have network operator specific SW version) eventhough the HW and SW(android12 version=58.2.A.10.126) support it?