I imagine it’ll be very similar to a air crash.
Gather every piece of the vessel possible and reconstruct it in a hangar or warehouse. Most likely the failure point or points should be pretty obvious.
Why would they bother? I understand in the case of commercial aircraft because there could be thousands of those aircraft still flying and it would be good to track down what failed. In this case, it’s a one-off, taped together by a goober in his garage. What could be learned that would justify the huge expense of recovering the shards?
That’s not going to be possible...they will never find the point of failure. The destruction from the implosion is so complete that the carbon fiber hull will be fractured into millions of pieces. Plus the fact that a significant portion is simply going to be lost.
Except there is HUGE motivation to diagnose then failure modes of crashed aircraft to improve the safety of future airliners.
There is about zero such economic motivation for deep-sea tourism subs.