Can you ever motivate yourself well enough to do the work?

If not, there are two options:

1. Recognize that you no longer care about the work and find something you do care enough about to push through the hard parts.
2. Find a different way to engage with the work, or use your strengths in a different way to make the work more engaging.

One might be the path you really want to take, but the other might be the more feasible option if you don’t have a lot of flexibility to radically change things.