Hustle before 100k ?

I listened to the “How to be an entrepreneur” course, and from what I understand, going from making 0 as a coach to 100k may require some hustle, and that it is different than the rest of business scaling.

Then, I listened to “Entrepreneurial Management” and the rule of not working more than 40 hours a week seems also relevant. I’m trying to reconcile these ideas.

Here is my particular example:

Circumstance: I’m going to start a coaching business; I’m currently an employee, and I decided to keep my current job (working 4.5 days a week) until my business takes off.
Thought: I need to work in the evenings in order to make my business take off.
Feeling: Courage
Action: Work evenings and sometimes Saturday afternoon
Result: My plan is moving forward

After listening to “Entrepreneurial Management,” I’m wondering if I’m missing something. I would appreciate having your opinion!

Thank you.