...electronic tracking devices that are automatically triggered on contact with water.
And their signals are not going to be heard after hard contact with water and the shallow sea bed.
If after a diligent search, no sign is found, then I think it inevitably points to a fast, steep impact with the sea. If the sonar signalers from the data recorders are buried in the mud in the tail, then the wreckage may not be found. Perhaps a trawler will eventually unearth something.