How about covering wall with lining paper and choosing an awesome wall paper for that wall

That's too bad, assuming the prior owner did this to the walls? I'd want to remove it or take it back to the studs and put up new drywall, cover it with beadboard, wood shiplap or something. If your new vanity is smaller, you'll probably find part of the wall behind does not have this anyway, so you will be forced to deal with it.