Cows milk/food question

So this is probably a really dumb question.. this is my first so please don’t judge!

But I see a lot of posts about switching to cows milk, is this instead of formula? Or is it just with their breakfast and things like that? I can’t understand how cows milk would even remotely fill my little one up! He’s 11 months so we’re nearly at the stage where he can have cows milk.

I’ve been doing the same thing with his feeding for what feels like months now, he eats the same amount at a meal time now as he did at 6 months old. Do I need to start trying to push more solids in in a meal time to fill up the gaps between meals to slowly phase out his bottles?

He generally eats about 150g of food and maybe a small yogurt after. I guess I’m just scared to push it and him be sick! He’ll have his breakfast, then lunch, then 5oz of formula in the afternoon and then his dinner. Then he’ll have about 8 oz of milk before bed, but has recently started waking up at 4am wanting a bottle, which makes me wonder if he’s not getting enough in the day🤔

Any advise or tips would be appreciated!