A similar thing happened to my mum. She had a TIA and went from hospital to an assessment bed in a care home. At the end of this period (6 weeks) there was a Best Interest meeting as no-one had Health and Welfare POA and I was invited so I saw what happened. The reason for the Best Interest meeting was to decide what would be in mums best interest after this assessment period - should she go home and what care package would be required, should she stay at the care home permanently, or should she be moved somewhere else?
During this assessment it became obvious that mum would require 24/7 care. Even having carers going into the house would not be sufficient. I was asked whether I could move in with her, or have her move in with me, but I could not as I was caring for my OH already, my home was not suitable for someone with mobility problems (she had problems with stairs) and before the TIA mum would not allow me into her bungalow. The Social Worker looked mum in the eye and said "Dont you want to go home?" and mum replied "I thought this was my home". So she stayed there and I was actually relieved as there had been so many, many problems beforehand.
Social Services do not like moving people from their homes and consider a care home the last resort, but they are legally bound to to take the person with dementias wishes into consideration. If the assessment has shown that your mum requires 24/7 care (and that means far, far more than just mobility problems) and she has also expressed the wish to stay there, then no, there isnt much you can do.
It is a shame that because of covid you cannot visit. I think that if you could go and see her in her care home and know what it is like you would be much reassured. As for the language problem - I think it is highly likely that there is at least one carer there who speaks Polish. I do not live in an area that is renowned for multi-culturalism, yet the care home seemed to have people of lots of different nationanaliries and backgrounds working there, including Eastern Europeans.