Siblings can be a handful, younger or older. Hopefully she overcomes these attitudes. You’ve done your best to help her learn from it by speaking up, the rest is up to her. Sorry that you’re having to listen to all that.
Of course, you can also speak to your parents/caregivers about how she makes you feel, as they should also do their part in not encouraging or allowing that to go on.
It can be quite tough. But just know, you’re not alone. So be strong in the meantime and hopefully she learns to be nicer to others through your resolution.
I can only imagine how wonderful of a person you are irl, the way you speak is nice and empathetic. More than anything, attitude is what makes people look attractive to another. It doesn’t matter how much hair and makeup or curves one has, if your attitude towards others are trash, then you will look very ugly.

erm does anyone have family members that make harsh comments abt ur appearance like all the time too
I'm ngl I'm not pretty, and my sister totally won the genetic lottery but DAMN she makes comments abt my looks and always compare us.. it's literally so draining to hear everyday