@rik Thanks for checking with iodé.tech lead developer.
@ronnz98 has not only implemented VoLTE/VoWiFi (Wi-Fi-Calling) in ROM build (A16) iode-7.5-20260607-a21s, but also Galaxy S9 (starlte), Galaxy S9+ (star2lte), Galaxy Note9 (crownlte). In addition, ROM /e/OS 4.0 A16 is also available for these three builds.