If it is pretty obvious that one has more mental resources and energy when they feel the effortlessness of living, the joy of life, wouldn’t you then agree that kids have something to remind us of - our birthright, of what most us have forgotten? One does not need to punish oneself to achieve one’s goals, and can instead see the journey to the goal as its own reward. And then no matter what you end up doing - you’re doing the right thing. No matter the result - you’re walking your own path and you know you are exactly where you need to be. Life becomes effortless. Do you think you’re ever going to experience lack of motivation while living such lifestyle? What an irrelevant question, isn’t it?
Ask yourself: is it at all possible that your supposed lack of motivation and ADHD are nothing but SYMPTOMS of you logically planning your life, logically deducing that which you call motivation? What drives you in life?