For me, creating a really defined picture of what I need to being helps a LOT. I have ADHD as well and it makes me not feel like doing certain things because they're boring and repetitive, or I just feel overwhelmed or don't know how to started. So I have lists with almost anything I can think of that needs to be done at some point. And they're categorized. I also have a projects list, for long term plans/goals/etc. And then I have actions lists for things to get me closer to them and whenever I think of something, it gets added. For any given day, I will add a few tasks in an app called ToDoist and when I complete something it gets checked off. It makes me feel like I'm actually making progress towards things, by breaking them down and making it so I have a feeling of satisfaction after I do. It also makes it so that if for some reason I can't accomplish much, it'll all be there tomorrow, and I can keep working on what I need to work on. I can just pick and choose what things to work on without as much much effort, except for like one day a week where I review everything and make sure everything is in check. I read a book called Getting Things Done that taught me this system. Changed my life. As for getting yourself to do things you WANT to do - I have a similar problem as well so I literally made a list of things I can do and pick from to make it easy for myself. Might sound silly but it takes away some of the thinking lol. I can just say, alright, let's to to my movies to watch list, and then I'll pick a random movie. It did take initial effort to create this whole system but it's been a lifesaver.
Anyway, I hope that helps maybe a little