How about four ships spaced 100’s of feet apart. With the ships having very round bottoms to allow for lots of roll (more like large buoys). Hang the net (carbon fiber?) up from masts to keep it up from the water.
Probably more expensive, but maybe less risk.
That would be expensive, considering the ultimate goal is to return to land. Spacex is close. IMO, the last attempt was somewhat successful. The rocket did land on the ship, but with too much tilt to stay upright.
I think if they didn’t have to aim for such a relatively small target, they would be successful. In other words, if the could trade lateral accuracy for vertical stability, I think they can do it. They need to figure out the margin of error before the government will let them try, though. My guess would be a radius of less than 200 yards for the margin of error.