HighWater is correct, and the suicidal deepstrike is fun, especially at Suicidal when the AI has all the other cards.
One can, for example, sort through the enemy planets to find where they have things like the soldier training bonus facility, the aphrodisiac trade good, the eco capitol, etc and target them specifically. If one spots re-invasion transports in-bound that cannot be stopped, one can raze the bonus facilities or even destroy the entire colony - - relegating it to a PQ 0 planet.
I have yet to test if, once a bonus facility is destroyed in the above fashion, if I can now build it myself within my empire (like the soldier training one). I think I have done it, but cannot now recall for sure.
It allows a bit of scope for role-playing.
Remember, also, that the first step is taking out the enemy anomaly mining bases!
In DA, the MCC is a conundrum. It gives a 100% eco bonus, so you do NOT want the enemy to have it. OTOH, if stops planet-flipping (a known DA bug). One "solution" I have adopted is to take it away from an AI, let my treasury build, evacuate the planet down to 1 colonist unit, then gift it to another AI, preferably an ally or a minor. The low population makes the game engine value the planet low, so I can always buy it back with tech later if I need a fresh cash infusion but, in the meanwhile, I flip some more planets.