does a series 5 apple watch need both wifi and a bluetooth connection to a iphone or will it work with cellar from the iphone without WIFI?

The watch works fine without wifi,I only use wifi when I update the watch apart from that it's always off,the watch talks to the phone using bluetooth and if your watch is cellular then it makes calls and sends texts through the phones service provider via an esim that is in the watch.GPS only watch makes calls and sends texts via the phone which must be in bluetooth range of the phone.