How to choose sip call without sim card?

Question

Android

Set up standard sip on redmi 5a phone.
When calling, you can choose: call from the first, from the second SIM card or via sip.
This choice is offered only when there are two SIM cards in the phone.
I remove the sim card / sim cards and you can not choose a call via sip.
Is it possible to somehow solve this nuance, including through editing the operating system configs, can anyone come across?
Because, as it turns out, to use sip you need a SIM card.
(the option to use third-party software is not interesting, just like using a "dead" sim card)

Answer 1

In this miui everything is very, very non-trivial. In order for the call to go through a sip from a regular or third-party dialer, the number must be in a certain way hammered into the address book, which is in Google. There, when creating a number, the sign sip: is set. Then if the sip account in the phone is clogged, then the call automatically goes through the sip.