Bottle weaning

Struggling mama over here! At my sons 12 month appointment the doctor said we need to wean bottle ASAP and switch to milk. He only has bottles first thing in the morning, one nap and right before bed. I’ve been cutting his formula with milk and am almost fully milk. But he refuses to drink it out of anything but a bottle. He can drink out of a straw and will drink water like that but no milk. Part of the problem is he still doesn’t understand that to drink out of a sippy cup you need to tilt your head. I think I have tried every type of cup out there from sippy, to straw, to even a fricken yeti cup! He loves drinking out of my water bottle so I tried to trick him and filled it with milk and he took one sip and refused. I’m getting a little frustrated and realize it takes time but I honestly see no light at the end of the tunnel. Please any tips, tricks, advice would be much appreciated!!!