Zuren, your best bet is as much mechanical agitation of the bottom as you can while the aeration adds the oxygen to the newly disturbed sediments and areas below them. IN a limited area one of those deicer jet pumps at the end of the dock can do a great job. It rotates and blows the sludge up and into the water column allowing oxygen under it and some dispersal. You might be able to move it from time to time and cover much of the shore line.

Deeper water holds muck and harder to get oxygen under that muck. I have envisioned a large trash pump discharge on a pipe and pushing up and down into the muck layer? Can you do that from a boat? Not sure.

Motor boat prop wash works in shallow water.

Fixating the front of a seadoo (safely) and using the jet output of water gives tremendous power to blast loose the layers of sediment on the bottom. Again, not sure how to direct that jet into the deepest waters. Respect the power of that jet so that no one behind you gets hurt.

Other mechanical means might include a long rope system and dragging a mattress box spring, or a home made metal drag back and forth through the deeper areas?
Some have create a long pole with large tined rake and attached that to the front of a front end loader mounted on a tractor to reach out and disturb and scrape out muck.

I have toyed around with another crazy idea. You have seen those heavy yellow metal 'tractor' sprinklers that pull hoses around in your yard? What if you had something like that, heavy enough to walk across the bottom of your pond. Then you hook a larger hose (maybe 1" from a trash pump) and then direct the water to a horizontal bar with downward directed jets. Of course the movement from the tractor sprinkler comes from spinning the arms on top which turns gears. Not sure how well arms would spin underwater but the whole contraption could somehow still be water powered to move slowly across the bottom.