vav can do different stuff depending on context too. not sure vav as a vowel indicator is as old as the tetragrammaton? i know some features of the writing system are later innovations - most accomodations to vowels don't go back to paleo-hebrew iirc, but the tetragrammaton probably isn't that old anyway.

Anyway if that vav is signalling a vowel, it could be an english o/oo sound, or a lot of things

I'm not an expert, i am just the specific kind of nerd that will slowly learn archaic languages at whatever pace i can manage and i've got subpar hebrew literacy for it, so i don't wanna mis-represent my credentials here.