I have cats and quilts. And a Dog, but he has his own quilts on the floor.
Two of the cats only use their scratching posts. One scratches wherever she pleases. None have ever scratched anything on my bed. They may knead the bed, but that is not scratching or clawing.
I have quilts folded over the sofa and a chair, the worst that happens to them is that they get cat hair on them. I am ok with that.
I do trim their nails as needed. There is no way any of the three would allow me to put the soft caps on their nails.
It sounds like there are other issues at play in this situation.