Length is just a guess on my part based on the image displayed and the legend of 42 meters. It appears to me that she is lying keel down with the tops of the frames and the deck beams clearly visible.
Yes, I think you are right, the wreck of the Guadeloupe has been excavated and this is certainly too small to be a 28 gun frigate. Closer to the size of the brig Betsy.
I hope that they keep the location secret, the last thing that they need is a bunch of “help” from amateur divers.
I don’t have a lot of experience reading wrecks like this, even with this high-frequency shot. Do you know if this might be indicative of a ship that burned, with the hull nicely intact, or is there no way to tell?