Oh Joey, this is another area where you & I have had almost identical experiences.

My elder brother was Mummy's perfect little boy, the one who could do no wrong. If we got into a fight when we were little I would be punished for hitting him, but if he hit me then according to my mother I was 'probably asking for it'. Also, he was a Real Boy™ (unlike Pinocchio here) so our parents put all their resources into making sure he'll be a good breadwinner. Aah, the 1970s.

Me? Well, I was second-born, so my parents were too busy looking after Golden Child to spend any time or effort on me; I pretty much had to raise myself. Oh, and lest we forget, I was also born female in the very sexist 1970s which meant that my parents didn't believe I deserved an education. In those days, girls were expected to complete their basic schooling before getting a job as a secretary or nurse, then marrying the boss or doctor who would of course support the whole family. So no uni for me, but my brother was sent to university because he had a duty as a man to support his family.
It stings especially badly to see your parents giving your cis brother every privilege, but denying you the same because they perceive you as female and they consider female children to be in some way less worthy. That hurts so, so much. And it hurts even more when you're crying out for help that they're not willing to give, because they're so preoccupied with the Golden Child.
But what you might not yet have realised is this: your parents have unwittingly given you a HUGE advantage over your brother, specifically by trying to hand everything to him on a silver platter.
You see, if your parents always do everything for you, you never learn to stand on your own two feet. Take your comment about him needing Mummy to cook his tea: he's an adult, he should know how to do this for himself. I bet he can't operate a washing machine either, because Mummy is happy to wash his stuff for him. But you? I bet you can do those things and more. Your brother has been so infantilised by your mother's indulgence that he can't even pop a ready meal in a microwave if he comes home late. You're already 10 times the man he is, simply because you've had to stick up for yourself and figure out how to do things.
My mother once said to me: "Success is the best form of revenge" and she was absolutely right. So don't let your brother's perceived advantage eat at you. See it for what it is: a huge disadvantage that he'll struggle to overcome. Just bide your time, get your education, and then sit back & laugh when you overtake him. Because I'll tell you this: you
will overtake him, because your parents' neglect has enabled you to find the courage, tenacity and resources to become an independent adult.
P.S. your brother likes girls too. If it's good enough for him, it's good enough for you.