If you want to use Evolution with VoLTE, then use version 4.4 and install Voenabler v1.8 (n eed root to flash it using TWRP). With ver 4.4 you have June Security patch.
Here's the link for Voenabler v1.8 (scroll down somewhere in middle of the page)
After trying many ROMs, I stay with StatiX OS, because it's very close to stock rom, simple, stable, has VoLTE, has double tap to close, AND they update regularly. Give it a try.
I found VoEnabler. Is it possible to use magisk to install it? Have you used it?