Tough question to answer because everybody learns and memorizes information differently. My 2 cents is it's not nearly enough. You can survey the internet and find all these threads about "all you need is the green book" but tbh those threads are talking about the old test, back in the 2000s-early/mid 2010's, before the question styles were changed and new information came out. I know that OMM doesn't change too much, but the way the questions are written certainly does. I tried using only the green book on my Level I and hated how uncomfortable I felt on exam day. It's not first line questions anymore, you kind of need to understand principles and apply that knowledge to a scenario you may have never seen before.
I recommend either (a) supplementing Savarese with OMG OMT / your other resource of choice, or (b) just abandoning the book altogether and sticking to the NBOME practice questions with whatever medium you learn best from (videos vs. q-banks).
At the end of the day, half the battle with boards studying is being able to exploit however you learn best and feeling comfortable with your choice of resources. So as much as I wish I could help, you gotta look inward 🙂 If that's reading textbooks, then sure use the green book. If that's videos or practice questions, then I don't really see why you'd use a textbook to study.