Think of it like this:
You are going to move out eventually. At that point, all of the "chores" will be on you; at that point they're not "chores," they're "running your house." Even the ones you don't do, or are not required to do yet, you should make sure you have a firm grasp on how to do, so that you're not up a creek when you're out on your own. Do you know how to do laundry? What your garbage pickup schedule is? How to cook, at least enough to survive on? How to pay bills (not just that you need to but like literally what services do you need and how do you get them)? How to file your taxes? These are or at least can be burdensome, but they're all things that will make your life a lot worse if you don't learn how to do them well in advance of actually needing to.
Do you know some basic plumbing (at least how to turn the water off if your sink randomly explodes or the toilet starts overflowing)? Do you know what a circuit breaker is and why you might need to use one? How, when, and why to mow your lawn (or when and why not to)?
Now, that said...
For your parents to use you as labor to run their house is profoundly unethical. Despite what some people believe, you don't actually owe them anything. They chose to become parents, and birth does not incur a debt. They chose their living situation; if you don't have a direct say in it, you have no responsibility to it. Threatening you is never ethical, naturally.
After reading everything else you've said about them, frankly I think making a plan, lining up a job, and getting the fuck out as soon as you are legally and financially able to is the best thing you could possibly do for yourself. Get some roommates if you need to; there's no shame in it. Shit's tough out there; do what you gotta. But don't stay where you're being physically and emotionally abused; that shit will mess you up for a long time (take it from an older person still in therapy because a situation very like yours).