It doesn't have to be perfect when you're starting out, either as a beginning writer or when you're considering a new process, genre, or approach.
It might be a big ol' mess, and that's okay. Sometimes we need the mess to figure things out.
But you can use this to your advantage. Instead of accidentally falling into the ugly version, cannonball with gusto into its mucky centre.
Do it with intention.
By embracing the bad version first, we get the nerves out of the system and keep our expectations low. We're not attached to it, so we can play with it and figure out how all the pieces work.
Maybe you're trying to figure out how to write a novel—use the ugly version instead of the special one you've been cherishing in your head for years. Maybe you're trying out a new genre—tell the generic story to feel comfortable in the form, and use all the overused tropes along the way.
It doesn't mean you must stay with the bad version or finish it. Use it as a testing ground to lower the bar.
That way, when it's time to do the formidable one, you've already dipped a toe in and feel a little comfortable.