My two cents: Meet them where they are, be patient (but consistent) with them and forgive them for COVID ruining their formative band year(s) during which they would have learned to behave like we all know band kids can/should. I hate to make excuses for them but I really believe that to be the case (my 7th/8th grade group is a bit of a nightmare, too).
My other two cents: The longer I teach the more convinced I am that with MS kids it is "do-or-die" important that they *like* you if you want them to behave and work hard for you (the alternative is that they *fear* you but that's not my style). Make an effort to connect with them every day, not just teach them. See if you can get to know them and relate to them. If there's a relationship there eventually they will slowly (very slowly) start to meet your expectations. From there -- why should they care about being good? Romanticize the idea of being a good band as opposed to a bad one. Being good is FUN. The only thing more fun than making music with your friends is being really good at it. Even more fun than that is putting on performances that make people say WOW.
Why do YOU love teaching music? Why was band YOUR favorite class? Maybe you could share that with them. Or better yet, SHOW them and see if you can infect them with it little by little.
Sorry for the sermon; it's just as much for me as it is for you. As I mentioned my 7th/8th graders are really difficult too, but the more I "win them over" the more I can see them very slowly and very gradually changing their behavior and rehearsing a little better day by day.
Good luck to you!