The things you’ve done and the way you’ve done them that have made it so that you’re about to take on more–they’re sufficient for the more. If they weren’t, the more wouldn’t be. Remember that when you’re making middle-of-the-night lists of new books you need to consult and new habits you need to adopt and new systems you need to put in place in order to succeed at the more. You don’t need any of that. You didn’t need it before and you don’t need it now.
You know that this is a bad case of Imposter Syndrome, and not your first. And you know the best remedy for Imposter Syndrome is forward motion, progress on one thing today and then another thing tomorrow. The problem with the books and the habits and the systems is that they aren’t forward motion. They’re lateral. They’re focused on you, not on the project(s) and the goal(s).
The thing about Imposter Syndrome is that real imposters don’t have it. It’s probably a good sign that you do.