My cat likes to scratch on this weird vinyl/fake leather chair that I have. I’ve tried covering it in tape, and he still scratches it. One day, I realized that whenever he scratches it, he almost immediately turns to look at me, so I started to wonder if he might be doing it for attention. On top of that, as soon as I tell him “no”, he usually walks over to me, looking for attention. It took a lot of patience, but since the chair was already ruined, I decided to try just totally ignoring him whenever he scratched the chair, and giving him positive attention when he scratched on his post. Somehow, it actually worked!

Another suggestion would be to put a scratching post as close as possible to the couch corners as possible, and when you do catch her scratching the couch, very calmly reposition her to the post. Praise her for using the post, completely ignore her for scratching the couch.

I know you mentioned that she has a cat tree nearby, but the geometry of the couch might be giving her a better stretch, she may like the material better, and/or she may be looking for a way to better claim the couch as part of her territory, as a scratching is also an important way that they leave their sent on things.

https://www.jacksongalaxy.com/blogs/news/how-to-stop-your-cats-from-scratching-furniture

Double-sided tape on the problem areas worked for our cats. But also make sure there are appropriate scratching posts available nearby.

You might want to try soft claws. They’re little plastic caps in the shape of a cat’s nail (except soft not pointed) that you fill with a non-toxic adhesive that comes with the pack and attach to the cat’s nails. Over time the cat naturally sheds their nails and the nail caps come off with them and you just replace them again when that happens. They say it doesn’t bother the cats and they don’t even notice but I think they’re exaggerating a bit there because my cats hate the process of having the nail put on which makes me feel bad but once it is actually on they quickly forget about it and it doesn’t bug them.

It’s not a perfect solution the claws are finicky to work with, the applicator for the adhesive gets clogged with dry glue, the cats don’t really like having the nails applied, the caps themselves are really quite expensive and some items like wooden furniture, still get damaged even with the soft claws but the damage in such cases is still greatly reduced and for soft items like a couch it pretty much stops them doing any damage.

One thing to keep in mind though, don’t buy cheap ones off eBay, they’re not worth a cent, the cats hate them for some reason, they don’t seem as well manufactured and they don’t come with little cleats inside to help lock it in place. Because the cats absolutely hate them so much and are definitely bothered by them they immediately pull them off straight after you’ve applied them and they’re just a waste of your time and an unnecessary source of stress for your poor kitty. I’ve found 2 brands that seem to actually be good and they’re both a lot more expensive then I’d like but at least you can buy a supply of several months and save your possessions from destruction. The two that worked for me are Soft Claws and Soft Paws. Claws seems slightly cheaper. I think they might actually be the same product since they have the exact same artwork and typeface for their packaging and logos and the caps themselves seem to be identical, one of them just says claws and the other paws. Weirdly enough they’ve both chosen to use Garfield on their packaging and somehow I’m fairly sure neither has paid for the privilege.