I'm glad to hear you're venturing out to your own side gig, as you said it can be super rewarding to do something you "want" to be doing instead of "have" to be doing.
With that being said,not sure I can agree with the "there is one surprising similarity between 9 to 5 careers and entrepreneurial ventures: success in either correlates very highly with how hard you work and your level of ambition to do well". This may vary from industry to industry but from my own personal experience, variables such as office politics, nepotism, poor management and being "black balled" all can play factors in your success, (or lack there of) in your typical 9-5. Not saying that happened to me, but I've known VERY hard workers that will forever be "stuck".