Sounds like you're at the end of your tether and this was the result, a last straw, which led to you attacking and injuring your own child.
I wonder if you grew up in a chaotic home? This kind of thing oozes down the generations.
Cut the 'poor me I'm a terrible person' crap - that's the sort of thing manipulative people do.
You're right to be seeking professional help, because you don't yet have the personal resources to cope with your situation.
Good that you have apologised. It won't be enough, so don't expect everything to be lovely and then get upset when it isn't.
Your children will be needing help too, after what they've experienced and seen.
I would say remove yourself from the house and find somewhere else while you work on yourself.
It will do your husband good to be the one coping with kids and a challenging teen and the house. He may find this changes him.
Your daughter is facing a frightening world out there.
She spent her adolescence under lockdown so her socialisation may have been impacted.
It seems she's never been taught how to look for work. That's a frightening process too, but at least that's a case of information and practice and encouragement.
I'm sorry this has happened, and that everything that led up to it was not adressed earlier.