Do you want covers you can take on and off depending on how muddy you are? Ive never found any particularly good ones that fit that criteria. Even waterproof ones ceased to be waterproof once you’re sat on them (bit like jackets are waterproof upto the point where they’re completely wet through).
I did have some cheap (but not waterproof) ones in my last car and from the front you couldn’t tell they weren’t original, it was only round the back where they obviously covered the fold up tables, pockets etc that it was obvious.
They were machine washable when they got filthy, and the watermarks on the seat came out with a bucket of water and carpet shampoo with a sponge, some elbow grease and hoovered off with the knackered Henry.