Start by being easier on yourself and forgiving yourself. I don't mean it as shrugging off the unacceptable behaviour, before anyone jumps on me. You say you want to be the best mum in the world to your little girl, this is inevitably going to pile on the pressure that will see you crack. Try setting your expectations to a more reasonable target. You just need to be a good enough mum for your child to be happy, nothing more and nothing less.
Then you need to work on defining your boundaries and upholding them. This is the hardest skill to master because it's not just about the parent-child relationship but about all other relationships in your life. If you can't set effective boundaries and say "no" effectively to other people, you won't be able to do that with your own children either. But to be effective, your boundaries have to reflect your personal values and convictions, not what others (parental experts, Mumsnet users etc) think they should be. As women we're conditioned to please and put others before ourselves so even just knowing ourselves is hard, and let alone standing up for ourselves and saying No.
When you are secure in your boundaries you will lose control over your emotions a lot less.
For all this I highly recommend books by Jesper Juul, a renowned Danish family therapist. Sadly not all of his books are easy to find translated to English but "Your competent child" is and it's essential reading.
amzn.eu/d/40Q8Mbf
I also recommend "The art of saying no" specifically on the subject of boundaries:
parentotheca.com/2021/04/13/no-the-art-of-saying-no-with-a-clear-conscience-jesper-juul-book-summary/
But start by forgiving yourself. The mistakes you've done can be rectified, you will make more mistakes, just keep fixing them and learning from them. As Juul says:
"It is much better for us and our children when we aim to be ourselves rather than try to “do the right thing”. Parents who are authentic are better parents than those who try to be theoretical parents. Parents who make mistakes and take responsibility for their mistakes are better parents than those who try to be perfect. Parents who strive for perfection will always make their children feel like failures and children who feel like failures often end up failing."