OP, you started dating this guy when you were 22. Prior to that, I wouldn't be surprised if you encountered mainly man children because unless you were dating way up in age (which tends to signal immaturity on the older party's part), they basically were man children, in the literal sense. So please don't think your teenage and very early 20s dating pool is an indication that's how all men are.
The real problem here is that you grew up and your boyfriend didn't. As others have said, you need to stop enabling this behavior. I realize that's difficult because you don't want to stand by watching him damage himself, and because some of the shit he refuses to do screws up your life as well. But if he never feels the consequences of his lack of basic responsibility because you're taking care of everything for him, he's has zero incentive to change.
That means you DO NOT take care of the things that only affect him. If he eats candy and cookies all the time, let him. If he won't make doctor appointments, don't make them for him. If he doesn't renew his tags and can't drive, you don't do it for him and you play chauffer for him. You can have a discussion with him about your concerns (for example, about his health) but then you recognize he's an adult and it's not your job or responsibility to force him to make better decisions.
On the things that do affect you, you sit down with him and divide up your mutual responsibilities. If you work graveyard, it is absurd that you get up in the middle of your "night" to mow the lawn. He needs to be pulling his weight with the household chores (including cooking, cleaning, lawn and house maintenance, and things like dealing with finances). You two should agree to a division of jobs, including how often each thing will be done (since he's doing zero now, you're probably going to have to be specific about the jobs, e.g. "cleaning the kitchen" involves x, y, and z tasks and needs to be done once a week"), and then you do yours and he's expected to do his. Your initial discussion should make clear that him not doing his share is a dealbreaker for you, and that you're not going to nag him or do it for him if he fails to follow through.
In the very likely event that he either refuses to divide up responsibilities or just doesn't do his, then I urge you to walk away. He's a grown man, and him choosing to behave the way he does demonstrates he does not respect you and that you two do not have compatible lifestyles.