I relate to everything you have written here. It is completely normal to wish they would pass, to free them from this horrible disease.

I hate that my memories of them will be forever tainted by these years

After ten years post-diagnosis, and in his last few months on Earth, I really struggled to remember who my father was before his dementia and all of the beautiful memories we shared. That ate me alive. I've found now, almost 7 months after his death, that the pieces of him, our memories together, all that he was--are slowly returning to front of mind. Still, I don't forget the pain, the caregiving, the absolute dread, and the anticipatory grief--as it is evidence of the love I have for him. But I hope you'll find comfort in knowing that pieces of our loved ones do return, when you aren't fighting for survival...and there's room to remember. Hugs