You are using VoId, right. They have the world's "best" routing. At least you are still getting VoLte, in their non-priority circle. We the VoId customers in their so called "PRIORITY CIRCLE" are not getting VoLte for months.
Another question, whether the speedtest server is Vi, by any chance? In that case they cheat by showing way too small ping and jitter. Try testing in Jio server or at least any non VoId server.