They will get their day in court, next month as that lawsuit is still moving forward, but at that point there will be no way to un-make the omelet (so to speak). The purchase will be completed and for intents and purposes Blizzard will be no more (as a stand alone company). The judge already said the FTC is highly unlikely to prevail in that court case anyways.
Lina Khan is already getting grilled by congress for her losing streak. All she's done as chairwoman of the FTC is turn the bureau into a joke. She's wasted taxpayer money on yolo cases on Big Tech despite the legal team telling her "no don't do that we do not have enough evidence to build a strong case" but she does it anyway. And all her cases are doing is forming case law that makes Big Tech stronger. She has to go.
On the bright side, with Microsoft owning Blizzard, it means the death of the horrible BattleNet launcher and Blizzard games finally on Steam.