I feel your frustration. I have been there, and am there with various children often.
My first thought was that you as parents, and he have not figured out what motivation he needs to make himself do what he doesn’t want to do. This will vary with the situation. For my oldest, he needs deadlines and to pay a late fee.
For my middle son, his next meal is delayed until he finishes his task. Phrasing it in a positive way. “You are welcome to eat as soon as … is finished.”
Parental attitude is key. They need to feel like you are on their side…on the same team.
Loveandlogic.com has many helpful materials.
My oldest son says that a negative attitude from the parent is the most demotivating force ever. If the parent conveys the attitude or says that the child is lazy, etc. then he gets angry and stops trying.
“I see you are struggling with this, but I know that you can do it. ”
Choices are always a good idea, even if they are small. He may want to have ownership or leadership of an area. He probably genuinely doesn’t know what type of work he enjoys.
Keep in mind that we all have certain tasks that we are not motivated to do. Try not to make him feel like his character is flawed. He simply has struggles.
Please don’t think that we have this all figured out. It plays out a lot more imperfect and messily that you are imagining. We have learned mostly from our mistakes.