[sandworm101]

The bad actors aren't down there with shovels and robots digging down into trenches. They are just like any other ship dragging an anchor across the bottom close to the cable.

These cables are often deliberately laid far enough apart that, should they need to be serviced, they can be hauled up by dragging an anchor/hook until it snags the correct cable. So it is equally not difficult to attack a chosen cable with nothing more complex than an anchor, a long chain, and a handheld GPS.