4 year old change after new sibling

I have a 4 year old daughter, who has been literally a perfect angel her entire life. Always kind, always listened. I just had my second daughter in November. My 4 year old is an amazing big sister and loves her baby sis. But seems to resent me.

My sweet and calm girl is now constantly talking hateful to me (and only me) and actively goes against what I say. She’s doing things she knows are wrong or against the rules. She’s throwing screaming crying tantrums, which she has NEVER done before.

I know this has been a big life change, and I have given her so much grace. I understand she was an only child for the last 4 years, and now she has to share but it’s just getting hard to manage.

I’m a stay at home mom and I try to spend as much time as I can 1 on 1 with her, it’s just really hard.

Has anyone else been dealing with this ? How did you fix it ? I just want it to go back to the way it was 🙁