I am deeply sorry for your lost. Losing such a beloved pet is a gut wrenching feeling and one that never seems to go away. I hope that you can find peace in knowing that you and your family gave that cat such a wonderfully long pampered life and that you and your family did everything you could to ease her passing into a new life.
This reminds me of a cat I had who died far younger than he should have. He was a mainecoon runt, perpetually all fur and bones despite eating more than the other cats in the house. He was clumsy as hell, constantly sliding his way into doors as he failed to account for his fluffy paws on hardwood floors. He manged to break so many glass cups by flinging them off counters that we had to get a whole new set. He lightly flooded the kitchen by skillfully knocking a plate over a sinks drain and turning on the faucet; a stunt he pulled so much we had to rubber band the faucets in the house to ensure he didn't hike up our water bill. But god did I love that cat. If anyone else picked him up he would struggle and cry as if the world had ended. But I could cradle him in my arms for hours and he was as happy as he could be. He was the first member of the house that greeted me when I came home from school and hearing his happy trills made me smile every time. It was hard for me to go anywhere in that house without his tall tail swaying next to me. He only lived till 7 due to developing a tumor in his leg. I sat with him in his final days when he stopped being able to follow me around, to jump into every nook and cranny, to snatch deli ham from the counter in 0.2 seconds, to spook me by launching onto my shoulder while I sat on my desk. Even in twilight moments where he could only sit in a box, even at the very end when I held him at that last vet visit, I could feel that little motor chugging along. His memory still makes me tear up, but I like to think I did the best I could for such a derpy cat.
In strange synchronicity, I have recently adopted a black cat just like yours. He is a spindly little love bug that can't seem to ever get enough time lounging and purring on people. I can't wait to see him grow into the healthy rotund void your cat is.
As a side note, since it is the spooky month I recommend people looking into the book "Ghost Cats of the South" by Randy Russell. Its silly and weird but its given me a lot of comfort to imagine all the cats that once were still causing the exact same cute chaos in some other realm. An afterlife without cats is really no life at all after all.