Valorant is too young to have a definite best region tbh
Just wait a few years, and we'll know. Because as of now everyone has their own opinion on what's the best region
People say that EMEA is the best region since they have the most international LAN wins, but EMEA has also shown many signs of weakness during 2022, and were being called a "one-team region", which in my opinion (might get hate for this) they are. There's always that one team that stands out from EMEA, which wins internationally, and the rest of EMEA takes credit for that, which is not a good thing for EMEA.