Update! Sock is warming up to me and he took treats from my hand twice. He even sat on my hand for a second before scurrying off. He also did what I call a "test bite" which is where a new hamster bites your finger or hand to kind of test if it's edible or something to chew on. Sock bit me twice but both times he was very unsure about it and quickly moved away when I pulled my hand away.
He seems very sweet and I'm glad the breeder already tamed him a bit because he's not skittish at all. I got some photos and a video:
https://vimeo.com/402713944