Feeling like a failure with my 4 year old

My 4 year old has turned BAD. An attitude from hell has come out. Every single day, she wakes up, says goodmorning and everything seems fine. Then out of nowhere, she just gets a huge attitude. She doesn’t listen, she screams at us, tells us to shut up, says she hates me, she will scream “you are being mean!” Even if you simply just ask “do you want breakfast?” It’s ridiculous. She hits her brother who is 1. She bangs her head off walls and slams doors. When she goes to the corner, she will stand there and scream “I’m not going” until you physically put her in there. Then she will scream “I’m done” until she comes out.

I’ve tried EVERYTHING. Talking to her, trying to get her to understand her feelings, redirecting the anger or whatever emotion she has but she doesnt care.

Today, we woke up and I gave her a hug and it was all good. She asked to watch frozen, and I said “not right now baby, we have to get breakfast started so we can go play” and she lost it because I wouldn’t let her watch it. I didn’t really feed into it, I was just waiting for her to be done and then she just starts yelling at my husband saying he’s being mean and she doesn’t like me, I’m not her mommy, etc.

I’ve tried punishment, corners, early bedtime, spanking, no toys, snacks, etc. I’ve gone the gentle route, to get her to understand, to hug her when she’s angry and that makes it worse.

I’m at the end of my rope, I can’t do it anymore. It’s been like this for a few months. Maybe longer. I know she’s a child, I know she’s overwhelmed with her feelings so I’m trying here but its not working