"If you want to be successful, work your 9 to 5, but then go all in on your 5 to 9."
Sorry. No.
If you want to be successful, go all in on your 9 to 5 AND go all in on your side hustle... but only for a couple hours each day.
Why? 5 reasons:
1. If you're not giving your day job your BEST efforts while you're there, you're just stealing... and thieves are not going to have the kind of successes they think they will have.
2. It takes a village! The people you currently work with can help you... Or not.
3. There are ALWAYS lessons from your "day job" which will apply to your "side hustle." Always.
4. If you wrap your whole identity and all your free time into the "side hustle" you WILL neglect things that are IMPORTANT not to neglect. (Sleep and perspective among other things.)
5. Constraints are your friend. If you think you have 8... 10... 12 hours to work on your "side hustle," you are going to waste a TON of time. What would you work on if you had exactly TWO hours and not one second more?
That's what you should be working on.