It looks like this happened back in April and Homeland Security blamed "an international hacking ring" which always sounds like a nation-state organization to me.
https://www.hawaiinewsnow.com/2022/04/13/hsi-agents-honolulu...
Even if an attacker seemed like they were a private individual, I'd lean toward assuming they were acting at the behest of some nation-state and just managed to cover their tracks well.
For criminal motive: I've read claims that some cartels have infiltrated telecom companies before, to track down informants or keep tabs on investigations. But from this angle, attacking cellular networks makes more sense than undersea cables.
[0] https://en.m.wikipedia.org/wiki/Narco-submarine
They have already taken several cell-towers, why wouldn't they add some fiber...
However, organized crime using unmanned true submersibles might [soon, or presently] be feasible. The expertise needed to actually attack a cable in a constructive manner would be a significant barrier to clear, but not inconceivable for crime organizations that can kidnap and coerce tech professionals. The ability to splice fiber underwater with a drone submersible seems extremely advanced though. I think only a few nations might presently have such a capability.
Nice summary of narco subs from HI Sutton: http://www.hisutton.com/Narco%20Subs%20101.html and https://www.youtube.com/watch?v=BR18qhnGEpM
I also learned from the YT comments that there is a theory that the Phoenecians might have crossed the Atlantic to South America, and that they might have brought back cocaine that was used by upper-class Egyptians. I expected this to be some kind of fringe conspiracy theory, but the Wikipedia page (https://en.m.wikipedia.org/wiki/Theory_of_Phoenician_discove...) suggests that anthropologists think it's totally possible, but lacking in actual archaeological evidence to support it. Cool!
I think your sense of geography may be off a bit.