Should I be using WorldRoot:GetPartsInPart() for hitboxes?

I'm working on a game with hitboxes. I tried Region3, but I'd been told many times that it's deprecated and also expensive. So I decided to use WorldRoot:GetPartsInPart() with OverlapParams, but people say that using actual parts for hitboxes is expensive. I'm not sure if I should keep using WorldRoot:GetPartsInPart() or switch to another method; at the moment, I can't really show my code, but hopefully, you understand what I'm trying to say. Thank you.