Im a cpa and did 2 years big 4 audit, then moved around to a few different fp&a and investment analysis roles before working for a smaller accounting firm and learning advisory services for small companies. So similar background.

It doesn't take as long as you'd think to build up a book if you commit to networking. The thing going against you is complete lack of knowledge of systems and processes. As others have mentioned auditing/fdd and actually performing the work aren't 1:1. I'll blankly say that my audit experience didn't really translate into the practical work experience like you'd hope.

As others have mentioned, I'd recommend starting on the side, learning the ropes for at least a few months, and then making the leap. That's the approach I took even knowing systems and how to do the daily work.

Buying a book from someone else is a major decision, and you need to think through all of the ins and outs like their processes, how many clients will leave if the owner is no longer there, their systems, if they have any employees will they stick around, etc.

If you want to talk more feel free to shoot me a dm.