I've nothing useful to add other than to sympathise. You and your Mum are at the worst part of this journey and there's a long slog ahead for both of you. I remember that terrifying, lonely, desperate, stage so very well.
All I can say is that you will find strength and determination you never knew you had. Dementia brings out the best in those of us who are burdened with a sense of love and responsibility. So many folk, as you've already discovered, are content to run in the opposite direction.
Your Mum's very lucky to have you. One step at a time, one day at a time, you will be able to help her. I beat my mother into submission with insistent, unwelcome help. She hated me for it. She threw me out of the house many times, made be cry with weariness and frustration, made me wonder what the heck I was bothering for. But the more she resisted my help, the more I knew she needed it. I learned to be as stubborn as her, not to worry about what other folk thought... and to duck!
One thing I will suggest though is getting to know her neighbours. Partly so that they know who to call if they're worried, and partly so that if your Mum loses the plot with you and starts raging (as mine did on many occasions) they'll understand what's likely to be going on. I was fortunate that my mother's closest neighbour used to be a nurse and has seen and heard it all a hundred times, sadly. She was not phased by the tantrums and occasional visits from my Mum telling her that I was a complete monster trying to take over her life.
I was trying to take over her life, sadly. But someone had to.
Best of luck, and remember you're never alone on this miserable road. It's just you can't see the rest of us struggling through the maze. However, thanks to Talking Point we can at least shout over the thorny hedges to guide and comfort each other.