A mobile floating dome that can move itself along the seabed?

At the bottom of the sea, various works are often performed by divers. Some such works can be done much more easily when a dome is placed at the bottom of the sea under which air is blown. Then workers under the dome can work dry.
The problem is that such domes are difficult to transfer to the location where the work needs to be done. For that, it is necessary to hire ships that carry the dome, lower it to the bottom, and after the work is done, lift it from the bottom. That is why such domes are made in smaller dimensions.
This problem can be solved by making domes that can float on their own, and then descend to the bottom and rise from the bottom.
In order for the dome to be strong enough it should be made in the shape of a half ball.
Such a dome (1) can be made with a wide tube around it which is like a hollow ring (2) located around the dome (1). When air is pressed into this hollow ring (2), the dome floats, and when water is released into the hollow ring (2), the dome (1) sinks to the bottom. In a dome, the pressure is equal to the pressure outside it. Part of the buoyancy of the dome (1) is also obtained from the air located below the dome (1), but this buoyancy is not sufficient to hold the dome (1) above the bottom. In order for the dome (1) to be strong and heavy enough, its walls must be made of steel slabs and thick reinforced concrete. The wall thickness of the dome (1) must be well calculated so that the dome floats only when the air is under the dome and inside the hollow ring (2), and sinks when water is released into the hollow ring (2).
In order for workers to be able to enter the dome (1) and exit outside on the side of the dome (1), it is necessary to install an exit. At the exit there is an exit room (3) with two chambers. If the diver workers enter the surrounding water then they come out from the lower side of the exit, and if they go out into some submarine then the pressure in the chamber must equalize with the pressure in the submarine.
The dome could also have additional elements inside, such as batteries for starting various machines and air injection pumps. The dome (1) could also receive energy with cables that would connect it to the ship floating above it.
Such a dome could be made in very large dimensions, because it does not have to be transported by ships. Under such a large dome, workers could work and rest for several days without going to the surface. When the work was done on a certain terrain, the dome would rise from the bottom by itself, and it would be moved to a new location.

My other innovations are shown in this book.