Regarding Defuse the Bomb, you need to ensure you have a higher raider to defender ratio.

Similarly to Kopervich and clan bases, the 'bomb' is the 'terminal' - and one side spawns closer to the bomb than the other. Because of the spawn advantage, the side with the spawn advantage should have 1-2 less players than the side that spawns further away.

E.g. Bravo spawns in the building next to the bomb, with 10 people at the training.
4 people should be defending (Bravo).
6 should be attacking (Alpha).