in the unofficial category and elsewhere in lineageos based roms there are experimental volte builds for the S10, S9, S20* and A21s containing (heavily llm-driven) descendants of phh prior ims work. They do have positive user feedback.
There’s now more ims implementation surface in AOSP Android 17 too.
It’s a silver lining for /e/OS Samsung owners to have volte calls work when 2G is sunset in 1-2 years. What does the murena team make of this: wait for aosp, use the llm derivation of phh/ims?