Two points I'd like to know first off:

How thick is the uncured resin you're dealing with?

Do you know for sure whether it's epoxy or perhaps polyester resin?

Whichever it is, I think the practical approach - labor intensive, yes - would be to mechanically scrape as much of it off as you possibly can.

From every surface you can possibly get a scraper onto.

Once that's done you need to address whether what remains behind will inhibit the bond between the wood and your choice of properly-mixed epoxy.

You may find some kind of solvent wash in order if you need to remove more crud than a scraper can.

Putting good over not-so-good, then finding out later you should have done a better prep, would be a sad thing.

   Thank you all - all I know is the boat was built in 1999 and I'm unsure what the person used for epoxy.

So I grew inpatient and wanted to make progress so I heatgunned and scrapped the entire deck. Didn't take that long. 1 full day to heat/scrape/then 80 grit sand with orbital the whole deck.  its now down to bare wood.

next up... the cockpit, best I can!

Encouraging progress then! Thanks for the update.