Liner stuck to hull

I think I see why my hull liner won't separate. Is this foam or glue? Feels hard. Any advice on how to approach this? There are a few of these blobs between the liner and the hull flooring. Project keeps getting harder. (Trying to get the liner out to replace rotten wood underneath.)
borescope video:

 

It's likely a big glob of thickened polyester resin. Stuff can sometimes be mindbogglingly tenacious. I've had to cut out the bottom of the hull around the stuff once, then saw the hull off and scab it back onto the boat. And believe me- I tried everything before I did that. (old 21' Atlantic my neighbor and I picked up for free)

 

It's probably a urethane glue commonly used on current boats, our 2018 Yamaha 190 SX is stuck together with it. The only thing that comes to mind is to tackle it with a hacksaw blade with some gorilla tape around one end for a handle. I helped my son pull the deck/liner off of an 80,s 21' Supra, it was not an easy task and they didn't have the expanding urethane glue back then. The urethane glue is slightly resilient and should give way to chiselling and the like but it would be a heck of a job to do. If you do; cut a lot of wedges to use between the hull and liner, cut away enough stuff and keep it tensioned and it'll pop loose.

 

It looks like expanding polyurethane foam, like the 'Great Stuff' foam used to seal around doors and windows.
My old Sunfish sailboats have something similar from the factory to bed expanded polystyrene blocks between the hull and deck.
I take it that the trihull has flotation foam between the liner and hull?