Frameworks and examples now exist showing how to gain this freedom. Jacob Lund Fisker[0]'s ERE[1] in particular is an interesting system theory based approach .
I invite you to read the book or read one of the interviews with the author. It goes so much wider than FIRE. Rather than a guide, it's an invitation to build your strategy. That should workas an individual or a couple, with or without children.
[0] https://en.wikipedia.org/wiki/Jacob_Lund_Fisker
[1] https://earlyretirementextreme.com