Ask for receipts concerning the paint. There are resurfacing resellers that will analyze a paint chip for you. Its important to know if its a rubber, acrylic, or (gasp) water based paint
It might be difficult to get an "expert" out to look at the pool. A plaster resurfacing company will blast it all off anyways.

So if the calcium hardness is low that can affect a new paint job?
Calcium has nothing to do with paint.

If I decide to resurface / repaint the pool my self,
how hard is the Prep?
roughly how many hours would it take 1 person to do it (56,000 Gal / 2500 Sq water surface area)
Or if resurfacing what’s involved?
Depending on the condition of the surface.....I'd guess 2 weeks of hard work every day for one person. A small crew could do it in 4 days.

It took me a long time to do my 40,000 Gallon pool but I couldnt spend every day on it.

Its important to get down to somthing solid....all the old paint must go. Is it a concrete base?

There are several good resurfacing options. You'll find many posts on the subject here. I went with a good epoxy myself due to cost, more expensive solutions look better and will outlast the best epoxy.

Good luck!