Can’t stress on this point enough. From my own experience, we tried all the 3 steps in our UX agency (and to fairly good success indicators) — but there was always something missing. I, personally, could never ‘detach’ myself from the work I (and our team) was doing.
I believe this introspection is always needed — “how easily can I ‘let go’ of what I, as a founder of a services business, have my personal stamp on”. If you can’t, then it’s a pretty solid signal that you’re not ready for scale, yet.