I want high resolution (<2m) imaging of the all the ocean floor.

I want to know where every missing plane, old shipwreck and lost city is and make a shit ton of money from this.

How feasible is this and what is the most effective way to pierce through the deep blue and get this kind of resolution?
The more ground we can cover with one sweep the better.
Imagine a couple hundred autonomous ships or subs going back and forth between continents.

Is side scan sonar the only way?
Is there anything in the electromagnetic spectrum that can illuminate 1000 meters down and get good images?