@DoloresJaneUmbridge is right, @lindsey33 - a care home is not the only possible solution, of the assessment does find that your grandmother isn’t safe to stay in her current home.
As I said earlier, maybe you could move in with her at night, with help during the day so you aren’t carrying the full load 24/7, or maybe she could be moved to a flat that is more suitable - on the ground floor, in a complex with a warden who would know which residents would need extra help to escape in the event of a fire.
And of course, if her condition has not changed since the recent assessment, she ought to be able to stay where she is, for the moment.
I do think you need to start coming to terms with the possibility that, in the future, your grandmother may need more care than you or the local authority can provide in her own home or a warden controlled complex, and that a care home may be the best thing for her. I know this will be heartbreaking for you, especially as you have been so devoted to her, but I am sure you want her to be safe and well cared for, if the time comes when you can’t do it any more.
My mum had this with her own mother - my grandmother lived with us for some time, when dsis and I were little because her mental state was deteriorating. My mum was desperate not to put my grandmother in hospital, but there came a point when she couldn’t give my grandmother the level of care she needed - she was getting too ill, and the burden of her care was impacting my mum’s physical and mental health - and she soldiered on as long as she could, but eventually my grandmother had to go into hospital.
Mum was heartbroken to have to make this decision, but it was the right thing for my grandmother, my mum and the family.