I’m just spit-balling here but...
Do the Chinese have an tracked underwater vehicle?
While we’re dithering on the surface, the Chinese just launch a few Glomar Explorers with a track chassis from the shore that haul it back up on the mainland. And we can’t do squat.
Hmmm... let’s keep this idea between you and me for now.
Locating the downed F-35 will be difficult under 3 miles of ocean unless the aircraft’s transponder is working. The aircraft’s trajectory to the floor of the ocean would be affected by currents and the wings of the craft.
They gotta pinpoint it first, and that will take sonar to accomplish. We'll hear all of that pinging, so they're not just going to sneak up with an underwater bulldozer and drag it off. We'll know something's up, and in a big way.
I believe anything “making tracks” along the ocean floor would have some serious zero visibility.