Late in the game, Marvel switched the conclusion to Quantumia

Ant-Man and the Wasp: Quantum Leap, the first adventure of MCU Phase 5, is now playing in cinemas and performing well at the box office. Ant-Man 3 generated more than $257 million worldwide in its first week, despite unfavorable reviews. The majority of it is generated by opening weekend sales.

But, given the Quantum Universe conclusion and its implications for the MCU, it is now clear that Ant-Man 3 should not have ended the way it did.

Marvel apparently reshot the ending at the last minute to modify it. We don’t know why, but we are aware of how the third chapter of the Ant-Man series ought to have concluded. There will be major spoilers if you haven’t seen Ant-Man and the Wasp: Quantumania.

Kang and Scott Lang will square off in Quantumia’s ultimate conflict. Jonathan Majors will play Kang (Paul Rudd).
The bad guy wants to leave the quantum realm and almost succeeds.
Even if it means being stranded and spending more time apart from Cassie (Kathryn Newton), Ant-Man is determined to keep him there.

Having delivered the potentially deadly blow that may have killed Kang the Conqueror, Hope (Evangeline Lilly) steps in to save the day.
Whether he is indeed deceased or not is unknown to us.

The Conqueror is believed to be dead by all other Kangs in the multiverse, according to the opening credits sequence of the movie. This awful Kang variation has already been banished to the quantum realm. They would not have dared to murder him, therefore they are upset that an Avenger did.

Quantum provides us with the supposedly happy conclusion we anticipate from such a movie when Hope and Scott return to the real world.
Of course, at one point, Ant-Man pauses to consider his choices after recalling what Kang had said to him regarding the fate of the multiverse. But it shouldn’t have happened this way.

Ant-Man and the Wasp’s first epilogue: Quantumania

We just witnessed a significant breach that exposed Quantumania’s subtitles. It wasn’t adequate to outline the complete storyline of the movie. But it supported a narrative leak from October for Ant-Man and the Wasp: Quantumania. The Quantum Leak took us right through the entire plot, right up until the very conclusion.

The only aspect of the storyline that is incorrect, when compared to the plot leak, is the conclusion. One leak claimed that Kang would have left the Quantum Realm, leaving Scott once again stranded. As a reminder, towards the conclusion of Infinity War, when Thanos (Josh Brolin) snapped his fingers, Ant-Man was imprisoned in the Quantum Realm for five hours. In the actual world, that equated to five years.

Scott wouldn’t have been alone this time. For him, Hope came back, but Kang imprisoned them both in the quantum realm.

Why did Marvel alter the conclusion?

Marvel’s decision to rewrite the conclusion is uncertain. The Direct, however, reminds us that Marvel reshot Ant-Man 3 in early January, almost one month before the movie’s premiere.

The storyline leak may have caused Marvel to alter the conclusion. There is no doubt that the new conclusion was not revealed beforehand.

Another hypothesis is that Marvel may have altered the main plot of the Multiverse Saga. It might be possible to leave the Quantum Realm without Kang the Conqueror. I would have wanted to see the bad guy leave. Maybe during the Secret Wars and the Kang Dynasty, the character was on the way to becoming a He Who Remains variation. But we never observed a body.

You should also think about Scott Lang.

At the conclusion of Ant-Man 2, Marvel abandoned him in the Quantum Realm so he could save the day in Endgame. No matter how much sense it would make for the Ant-Men and Wasps to remain trapped there, pulling a similar climax for Ant-Man 3 would have been weird.

The truth might never be known because Marvel frequently alters its stories while they are being produced. Reshoots for MCU movies are a common occurrence, and some of them are more involved than others. The aim is obviously to have a fantastic script and stick with it while trying desperately to prevent leaks, but perhaps that’s an issue Marvel has to tackle.