Rick Rubin, Huberman Lab
Run The Four-Phase Creative Cycle
Set a deadline only once you reach the final editing or completion phase.
Rick Rubin says
The first phase is this seed collecting phase. In the seed phase, there are no deadlines, it is just a wide open part, and the same goes for experimentation. By the time you're going into the completion phase, which is the final edit, getting to the version you can share with the world, you can have a deadline and it won't hurt the project, in fact it might help the project. Some projects have gone longer than they necessarily needed to, maybe not in the best interest of the project, because that wasn't understood.
Try this
Identify which creative phase your project is in, and only set a hard deadline once you reach the final editing or completion stage.
