You haven't 'got it wrong' but you can certainly start to cut down on formula now . My DD hardly ate at all until about 18 months, and got by on breastmilk and carby foods. She now eats a huge range of foods, is still BF but has plenty of cow's milk, water, and a bit of fruit juice. And she's finally put on some weight!
Children adapt differently so just take it slowly, and adapt to your child's preferences and needs. It was only when my DD was 15 months that we discovered she had a lip tie which was getting in the way of her eating - after it was resolved she ate much better.
Cow's milk is fine for a 1 year old, and certainly it is cheaper than formula milk. The UK govt advice is to give 300ml of cow's milk for babies between 1 and 3 yrs old (NHS page here) - the reason for this amount is to get the recommended 350mg of calcium. There is more calcium and less sugar in cow's milk than in formula.
It's not necessary to give more than 300mls milk alongside a varied diet and plenty of water.
It is also worth pointing out that the UK govt advice is to stop using bottles from 1 year old, and to use open beakers or free flow cups for milk (NHS advice here).
You say your dd is really happy and healthy so I wouldn't worry tbh! Afaik formula is just cows milk with extra vitamins etc in it, so it's not bad that you're still giving it to her but you could just swap to cows. I live in France and people here give follow on formula milk til they're three!
4/5 bottles does sound a lot if you're talking 9oz a time though. You could start gradually reducing and shell replace with solids. My twins who are nearly a year still have 3 bottles a day.
I live abroad, I dont have any family around to give me advice on the wrongs and rights with my one year old. I have just returned from a holiday in the UK and a friend with a baby 2 days older than mine told me hers was exclusively on cows milk(from a cup) and 3 meals per day. My DD is a great weight and very happy, somedays she eats like a horse (BLW eats anything) and then others is not interested in food. I havent introduced cows milk and she is still on FF - up to 4/5 bottles per day. Am I wrong? She she be on cows milk now? I was going to start introducing it this week now we are home. Am I filling her up with FF and stopping her eating? Am I doing something wrong? Help me please!!!