But in my mum's case, it's the opposite as she has never taken advice from anyone in her life!
My mother is the same - very very difficult.
I got POA last year - just in time as it happens, but I was on tenterhooks until it was all signed and processed. Like you she is self-funding and totally resistant to any help, and I knew I could do NOTHING unless I could write the cheques etc... for care.
From what you are saying, I think your priority shuld be to TRY and get POA asap. Otherwise you will have no control over the situation.
Do you have a solicitor whom your mother trusts, and who understand the situation ? The solicitor needs to see your mother alone to be sure she has capacity to sign the POA. My mother had enough capacity to do this last year - but still refused to sign for me (she wanted her granddaughter instead!). I tried flattery, but that didn't work, and in the end, I lied and told her that if she didn't sign the POA, then Social Services would step in and we would have no control over where she went, or what happened. I said that if I had POA, I could help her stay in her own home - which is what she wanted.
That is what I did, for months, but it didn't work - she refused "outsiders" coming into her home to help, so she has now gone into a NH.
If I had not had POA, I can't bear to think what would have happened - she is just so resistant and strong-minded!
Even if you do get Deputyship from the Court of Protection, I believe you are in a stronger position if you already have POA.
Good luck...