My Galaxy A14 5G only has setting for 'wifi calling'. Nothing for HD Voice or switching from 5G to LTE to older networks. I think it's all automatic now. the last smartphone I know that had the setting was my Galaxy S5, where under settings-->connections-->mobile networks it had a toggle for 'Advanced Calling' which was VoLTE compatibility, but that was 2014.
In the U.S., you can still put an active SIM into something that's at least 4G LTE like a Galaxy SII Skyrocket, LG Lucid 3, or LG G2 and you can still do SMS/MMS, data, email, but phone calls fail (they just sit there 'dialing...' until they give up)