2003 Warrior fiberglass
I moved the captains chair in my boat and never sealed the old holes in the floor.
Just noticed last year the plywood has delaminated. Seems to be just the first layer bubbling. The area is about 2'x4'

I am not sure how I should fix this. My first thought was to find a two part epoxy and try to glue the pieces back together.

If I remove and replace I'm not sure if I would find support for the replacement, and I have never worked with fiberglass before.

Also not opposed to having a well qualified and recommended shop to do this for me.

Fix it right. I’m sure not qualified to advise you, but it will plague you later if you don’t do it right. Please let us know
what you do. I bet someone else will benefit from your experience.

I'd take it to a glass guy, quick fix for someone who knows what their doing, probably a hours worth of labor

Check with Scuba 1 on here, he did that stuff professionally.

I would grind / sand the loose layer out, fill it to make it smooth then glass it over and then put new carpet on the whole deck. Not a difficult repair

It will depend on how deep the rot goes as to the fix. Usually what you see on top is the tip of the iceberg. I would cut back to the stringers on either side and replace that section. Glass the plyboard on the bottomside then install to the stringers, then glass the topside. You probably would do a better job than the manufacturer. Ypu wouldnt believe what leaves the factories covered in paint and gelcoat to hide poor craftsmanship.