Since they don't appreciate what you're doing, I would suggest a little test. You get your own stuff, clean your own thing, maybe do your husband's laudry max and observe how they will react. Also, stop cooking for the family one day a week if you can. If they get mad when you're pulling your own weight, you'll know they view you.
Also to limit your frustration, keep strict boundaries to low contact with BIL. Don't let him disrespect you and if your husband gets mad tell him that while he's okay letting his brother disrespect you, you are not and you will not be treated like crap by a edgelord wannabe. Tell him that at least it's good to know that he doesn't have your back to the point he's not even telling his brother to be polite. You'll do your own thing.