Solid food, bigger bottles, etc.

So a little info. Baby's almost 4 months old. She takes 4oz bottles every two hours during the day, then 4-5 hrs during the night. Recently she's decided she sometimes needs another 4oz bottle an hr after. Averaging about 32-36oz of formula in 24hr period. I've tried to gradually up her to 5oz, then 6oz but find she will finish them for a day or so then goes back to the 4oz. I don't want to waste formula but was hoping she was ready to take bigger bottles less frequently and maybe even sleep at night 😅.

My friend's son is 2 weeks older and he's already eating food, sleeping through the night, drinking 6oz bottles and she also puts rice cereal in his bottles. He's only 1 lb bigger than my daughter.

I'm wondering if I should try this as my grandmother claims it worked for all her kids (rice bottles) to get them sleeping.

Reading online there's many different options and same with doctors. My doctor is older and he said food at 4 months. Can try rice bottles just not super thick. Yet my sister's doc said not do that. She fed my nephew food at 16 weeks n he was fine, he's a healthy strong boy. My SIL EBF the twins till 6 months and then started food and they're almost three and look thin and always have a cough or cold.