1 year old transitioning to milk

My baby is turning 1 next month 😭😭 we have almost completely weaned off the bottle because he was sick of them at 10 months and preferred the sippy cup so that’s how we give him water and formula. I was curious how everyone switched to cows milk or did you choose a milk substitute? What are the pros and cons?

We have his 1 year check in next month so I’m obviously going to talk to his doctor about all this but wanted to hear some others experiences. Do you slowly transition like half formula half milk or full transition at a year?

Thanks so much!!