> VoLTE is 5G
Technically, on 5G you have "VoNR"[0], where VoLTE is over 4G.
Which AFAIK is only a thing in China. Most network outside it are still stuck on NSA 5G, let alone VoNR.
VoLTE can very well be 5G now, and it can vary from country to country, but my first memoryof VoLTE is originally started with LTE/4G networks.
3G networks in many European countries were shut off in 2022-2024. The few remaining ones will go too over the next couple of years.
VoLTE is 5G, common throughout Europe. However the handset manufacturer may need to qualify each handset model with local carriers before they will connect using VoLTE. As I understand the situation, Google for instance has only qualified Pixel phones for 5G in 19 of 170-odd countries. So 5G features like VoLTE may not be available in all countries. This is very handset/country/carrier-dependent.