Baby boy struggling to move onto cows milk/sippy cup

Li

My boys 1 next week so was starting to wean off formula and his bottles. He’s fine drinking sips of water from his sippy cup or an open cup but refuses to sit and have milk at all if it’s not in his bottle. He’ll just run around chucking milk everywhere 🙄😂 his first bottle I gave him to try cows milk he downed the whole thing but since that pulls the worst faces even when he even has a tiny sip.

He eats really well so I’m making sure he gets snacks etc instead and it has only been a week but any tips on anything that might help would be great thanks! We’re still giving him morning and evening bottles as before he was still drinking 4 bottles a day but I think it was out of habit as seems fine with snacks instead. I’m just very confused!