Motivation runs like a bus with no schedule. Walk.

Motivation turns up unpredictably and leaves on its own schedule, so building a plan around it hands your progress to something you do not control. Walking is slower and it works every time. The people who get somewhere are rarely the most inspired ones, they are the ones who kept moving at an unimpressive pace while waiting for a feeling that was not coming.

Choose a version small enough to do while feeling nothing at all. Ten minutes, one page, one set. When motivation does appear, treat it as a bonus rather than the thing you were relying on.