I'm hope your surgery went well and you start to feel better soon.
You are probably not feeling great right now, so I really hope that what I say doesn't sound unkind - but you have asked for our opinions.
I think the main thing is that your daughter is taking unpaid leave to care for you. This is a big deal and yes, it is absolutely what she should do, but still, many wouldn't. So be proud of her for that - you have clearly raised a kind young woman who is sensible if her responsibilities.
She came to visit you, which is another positive.
Yes, ideally she would have bought you a gift - I always take something when I visit people in hospital unless they explicitly ask me not to.
But I wouldn't have castigated my child for not doing so. Not when she was already doing a lot for me. I imagine she felt humiliated and hurt, especially as you did this in front of another family member.
As for her eating a couple of your snacks - is that really a massive deal. She was visiting you and had made the journey & maybe she was tired after work or whatever else she had been doing, didn't have time to get food, whatever. She offered to replace them when you raised it - so does it really matter?
You make a lot of comments about how independent you are, how you can't accept help from others etc, yet you sound in this instance quite keen to receive help from others to be honest (which is fine - no woman is an island). But maybe she is sensible or the dichotomy between your words and behaviours and finds that tricky to deal with? I could be wrong - it's just a suggestion.
I am not suggesting for one second you are wrong to want and need support, or in any way unusual. The vast majority of people are pretty independent - few of us rely heavily on others to get through day to day life. Except when we have to - when we are ill, or whatever. Then we have to. It's totally normal and totally fine.
I truly hope you feel better soon. Maybe get some sleep and you will feel better in the morning.