Am I doing something wrong?

Hey momma be kind to yourself you are doing an amazing job! You are honestly not doing anything wrong there will be days when your little one eats more and some days he will hardly have anything. Don’t rush to make your boy independent just because that’s what’s expected from us mums.
Instead of getting him to drink from a cup could you try something with a straw so he doesn’t have to tilt his head back.
Also with milk I wouldn’t be too focused on that he has to have the 16oz he can get his calcium from other dairy products too like cheese, yoghurts etc. also there is no rush to move him onto full fat milk straight away. I slowly phased out formula with both my girls 7 and 2 and they introduced milk to them
Once my little girl turned one I started focusing more on food and if I felt she didn’t eat much then I would offer a bottle about 30-45 mins later so she’s not going hungry.
You say your little one woke up hungry at 5am, when was his last feed/dinner?

I honestly continued to give my DD milk as shes a fussy eater, also give her flavourless vitamins, ur DS is still quite young, dnt be so hard on yourself! Its the toughest job in the world and it does get so overwhelming, but the fact that u want to get it right proves youre an amazing mom! Kids teach us patience, give yourself grave, maybe give him a tiny bit of water in a cup and let him practice and if he mkes a mess its ok they will eventually get it! And the comparing really pisses me off, my DD is on the smaller size and we always hear shit from the family, i always said my DD is perfectly healthy for her age

My daughter is 18 months old and honestly she doesn’t eat much food and she also doesn’t say that many words just a few of words here and there are some words she used to say but now doesn’t say them at all

I get what you mean about the comparisons my daughters cousin is 5 months younger than her she says a lot more and probably eats double what my daughter eats noon compares them but it’s hard not to notice sometimes

With Water my daughter drinks out of a tum tum cup and it took forever to get that she only started at around 13-14 months when I went back to work

Your doing nothing wrong

A baby waking up at 5 am isn't abnormal. Waking up hungry isn't abnormal either. If your little one isn't losing weight, and eats till he is full you are doing fine with that. Everyone's appetite is different, and children's appetite changes a lot from week to week. Especially with growth spurts.

He will get the hang of how to drink from a cup, just be patient and gently guide him when he tries.

As for the stairs, the gate sounds like just a mental block to get through. Coax him through and up the stairs patiently.

As for comparing kids, try not to you. People compare, and every child progresses differently. So comparing should be taken lightly.