That being said right now, especially as a first year teacher, it's time to let go of this and just teach whatever you're going to teach. If you're really not happy see if you can find somewhere else to work. Otherwise do your job and don't worry about his. To some extent as a HD I can honestly understand where he's coming from on the assignments over this time. This is not easy in the slightest on anyone!
Ultimately you have to make a choice here, because especially if they've been there a while it is THEIR program. I know that sucks to hear, because I've been there. I watched a lot of things go by that drove me nuts, but in the end when I took over THEN I was able to correct them because it became my program to make the decisions. As a first year teacher you still have the superpower of unlimited energy. (And right now probably being more comfortable with this distance learning concept than older teachers) First year teachers often think they know everything (I sure did), but there is a bigger picture you'll get five or so years down the road.
That's not to minimize the situation, but I would advise you to let it go at this point. No good will come from you pushing things now in this situation. If you don't think you can live with it another year start applying for openings. This is kind of a bad time to make a job jump though... Seniority is usually a factor if we end up in Financial Exigency status with our districts next year and jobs start getting cut. (Won't be surprised if we do... Only thing that will help is I think parents might be slowly grasping how much they need schools...)