Look online for your area of people who do leather repair/dying. Although I do a lot of my own upholstering, making window treatments, I'd leave that to the experts.

It will cost less to replace it than to strip it and dye it properly by a Pro. Painting? I can't even. Massive paint flakes shedding to go along with the dog fur.

A slipcover is the cheapest solution.

I actually did this two years ago.

Here is a link to the product I reviewed.
https://www.amazon.com/gp/product/B00VQVD4BE/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

If you will look at the reviews with photos , mine is the sofa that was tan and I changed it to dark brown. This was December 2016 according to the review. I posted a lot of photos of it, and put extensive instructions based on my experience.

Am I happy? Heck yeah!!!!!! My thirty year old sofa still looks great two years later, even though it’s the dog’s favorite napping place (because he can look out the window and see when we are walking home from town) and the cats sleep on it, too. Scratch marks, as shown, but that’s just normal with leather and pets, and I could touch them up if I weren’t so lazy. Besides, I like it looking a wee bit worn.

Two warnings. The stuff that removes the old finish is the worst smell EVER. I honestly though we might have brain damage from it. If you have a bird or small kids, try to do it in the garage, but the smell may still get in the house. And second, make sure you really get in all the cracks and crannies. When someone sits on a sofa, the cushions change shape under the weight and will expose areas you missed.

The little cotton wand or swab that comes with the dye looks ridiculous, it my dad did leatherwork. They are perfect for the task, lint free, and actually cover a lot of territory quickly, and prevent you from being overly enthusiastic and using too much dye. You can order extras cheap.

And do clean and vacuum. And de-crumb it before dyeing.

We also sprang for newer taller sofa feet to try to help with the 80’s appearance.

Going light to dark worked fine. I don’t know if it would work to go dark to light.

And rub it down with Leather Honey once in a while to keep it supple.