The disco is a trap, don't make it early. The way i beat it in brutal is terraforming all the entrances and making reefs in the small ponds, then using lobster to move them around so i can use them to disarm and capture enemy detriments that jump over.

Another approach is building "Seawolfs" in a loop.
Trying to catch all the Detires in the water with as many Seawolfes (~20) as possible and destroying the strider hub and everything else they can reach :)
You will loose a lot of them but it worked for me

detriment/shogun dies vs submarines, reefs disarm them very effectively, disarm, send in submarines.

terraform the side entrances with like 20 height, hovers will not be able to cross that, then some air defence on the cliffs and you should be set, get the antinuke, reef disarm + submarines.

yes, its a difficult mission, because of how many things go on in it, you can slow down the game, i think its mentioned in the mission info.