That is more than your classic C&C smile for sure. Dead stop at 6 knots I would expect some interior framing delamination, maybe bulkhead tabbing too. Get a pro to look at it thoroughly inside and out. First clue in the bilge will be the white gelcoat paint lifting off the the frame bed, maybe tearing or stress cracks in the frame corners. Does the head door close square, bind, uneven gaps between door and frame?
The least you will need to do is grind away the fairing material on the keel that is loose, grind lead to create bonding surface, fair it out in epoxy. But you should also expect the need to torque the keel bolts first.
When the boat was lifted at haulout - was there a gap between the keel and the sump? When hanging can you push the keel only sideways? If so, it may be time to drop keel, inspect all bolts, complete any repairs, rebed and torque bolts.
I sail on an '85 C&C 32 and there are tell tale signs like above of previous damage and repairs. Whoever did the repair got it right and boat is sound.