In order to deal with executive dysfunction, what works sometimes is to just do a little. E. g. instead of a full workout, I say: I can't do a full workout, but I CAN do 1 pushup, or 1 set.

Sometimes, I can do more with 0 mental effort, only the first one is hard.

At other times, I still don't feel like it. And here is the trap: I could force it like "come on, now you started, you finish!"

But the problem with that is that next time, the "just start" method does not work. The devil on my shoulder would say: "You know it's never just one pushup, more will be forced and squeezed out of you!" And he would be right.

Better to deal with nearly 0 progress occasionally than to lose the method! Be honest to yourself. If you said just 1 pushup, just do the one. More only when it's 100 % motivation-driven.