Likewise my PBI was 10+ years ago and money well spent, did mine in the Solent and loved every minute of the prep and assessment.
So long as you have the experience of both powerboating and teaching/coaching then you will be fine, you do need to know your stuff and your limitations (no good being over confident) and it is rightly challenging.
I agree with the comment about PBIs who do not have a passion or flair for the sport, my suspicion is that sail instructors get the ticket to be able to offer the Safety Boat course.
Once you are qualified you will probably want to get some experience as part of a larger school, going down the one man training centre route is a lot of admin to get started. No idea what freelancers charge, but in the SW the level 2 prices advertised to customers is 250-300 per person and increasing slightly due to demand and virus restrictions.
One tip - do not stray from the PB2 syllabus, its is easy to go off into Dayskipper, Intermediate or SRC material and thats best left as a teaser for the client's next course.
Best of luck and give me a shout if any of you would like to observe on a couple of courses either before or after you qualify (no charge or pay).
We custom design and build models of RIBs and other things, great for teaching aids, promos or gifts: www.plymouthseasafety.com