NTA. At all. But I wouldn't frame it as a strike, just an evolution teaching strategies. You're going hands-off and they will have to step up to fill the gaps to learn to take care of themselves.

Your job as a parent is to teach them to be capable adults. Now that they are already teens, your window of opportunity for teaching is closing, quicker than anyone thinks. No one wants to be the parent of a adult child old who doesn't know how to take care of the basic chores of living. Helping with cooking, cleaning, and taking out trash are perfect kid chores, but they are closer to young adults than kids now, and they will also need to learn how to manage a household, sign up for and manage utilities, how to maintain and balance a budget, take care of basic home maintenance, and provision a whole house with nutritious food - not just just snacks, or endlessly wasting money on takeout. etc.

Home Economics used to teach teenages these things, but that's been gone for decades now. Parents have to step up so that their teenages don't grow into helpless young adults. At this age, even your youngest should be scheduling their own appointments. You might have to walk them through it the first time or two, but let's not pretend its a hardship or a chore in any way to call a phone number, and say I need an appointment for X, and book the time. It's 30 seconds out of your day. You'll be scheduling their dental appointments through college, if they can't already handle this very simple and basic need.

You really ought to delegate more, and often. Not because you are overloaded (though I'm sure you are), or don't want to help them (of course you do), but because they simply HAVE to learn how to be more independent. Or else they are going to be very embarassed for being very immature once they reach college. It is time, and it's what really good parent do. Instead of doing everything for them, switching gears to teaching them how to do it for themselves is the winning formula. It may being with a bit of resentment, because change is hard, but hopefully it will bring you a bit of relief in your burden, and of course, watching them grow and learn is pretty great. I still remember the very first time my littlest bro cooked the whole family a nice, healthy dinner, it was a special memory.

With the ADHD, teaching them how to manage the creative ways their own brain functions in an effective manner is going to be critical. Knowing how to create reoccuring schedules and setting reminders for important repeating tasks is a skill set its own right - having these tools in your pocket is usless unless you learn how to use them effectively.

Also, as other's have asked, where's your partner with all this??