I don’t see why the carers are being so nasty and trying to stand in your way.
Just be careful that you don’t build up a fantasy of what it will be like with her. Just accept what you get and accept you mum for what she is.
Not sure what you can do about the carers but it shoulnd’t be up to them if you see your mum. I hope I’m not maligning anyone, but maybe they are worried that if you are back in your mums life then they will be out of a job. It could be something simple like that. I could be wrong.
Don’t give up. And keep trying.