How to deal with resentment towards a biological sibling who was kept?

Hi everyone, my biological mother gave me up for adoption as a baby. She already had another biological daughter, who she kept. I finally started processing everything years ago. I spent most of my life believing the lie that I was "rescued from a bad situation" by my adoptive family, even though unfortunately my adoptive parents were quite toxic. I realized that I had grown up expecting my biological family to be living in poverty or other terrible conditions. However, once I got my original birth certificate, I learned that my biological sister actually had a really blessed life. My biological mother got her life together after giving me away, so my sister has a strong support system and sense of self, multiple degrees, and has traveled all over the world. The resentment I feel towards her is really hard to process. I understand fully that this wasn't her fault, or her choice. But I have a hard time even thinking about her because I feel like I was thrown to the wolves and she just got to live her life freely, mostly unharmed, and with a strong connection to her roots. I understand that my negative feelings are actually mostly directed towards any parental figures in my life, because they failed me, but it's hard not to feel this towards my bio sister as well. Has anyone else experienced this? How did you process it?