Its normal.Dementia wise.
Definitely carry on with the cleaner and if your Mum tries to stop it remind her that its for you (Purnima) not her, as you havent got time to do everything.
You can hopefully be there when the cleaner arrives make sure she gets in ok, and decide whether its appropriate to give her a key? and tell her to just remind your Mum that she's working for Purnima not for Mum.
A few years ago Mum was admitted to hospital after a fall. It was actually on that admission that she was diagnosed with dementia. Went to see her one day and the nurse said to me "she's still declining". I was worried because I thought she meant Mum was getting worse. But in fact declining is the medical-speak for refusing help, refusing treatment, etc. My Mum declined everything that was offered to her unless it was something she thought of herself. And she would never help herself!
Eventually Mum was discharged to a care home, for continued assessment. She persuaded them to discharge her, on condition that carers called 4 times a day.
I think PWD dont like change but also often gradually lose insight, so they dont understand what is necessary. Also can become very controlling. Dont forget, this is a phase in your life which will pass. They more you involve others who can help, the easier it becomes.