Distressed vinyl liner pool to fiberglass

I have a vinyl liner pool. its 20 by 40 and it went down about 10 years ago, the liner was not replaced and now I'm looking at remodeling it. My question is, what are my options going to fiberglass? The walls of the pool are intact, the liner is basically gone, the poolcrete is basically gone, but the stairs or okay. I know that I can have concrete poured and then fiberglass resin painting over it, which seems pretty costly what are my options of having a preformed fiberglass pool place in the hole? And what are the costs. I have priced replacing the liner and I priced it doing it myself. But before I decide to do it myself, I want to price fiber options.from what I understand fiberglass may be more expensive initially but long-term is going to be the most cost-effective. Any information would be greatly appreciated thank you