The anime ending of Attack on Titan varies from the manga. The manga might have presented a more detailed or nuanced conclusion compared to the anime. It's a matter of debate among fans as to which one is better.
The ending of the manga saw various plot developments and character fates being decided. It left a lasting impact but also sparked a lot of discussions among fans due to its complexity and unexpected elements.
The alternate ending might deviate from the original in terms of the resolution of the conflict between humans and Titans. In the original, it was a very specific and somewhat controversial ending. The alternate ending could offer a more peaceful or a more extreme solution to this long - standing conflict. For example, instead of the destruction and transformation that happened in the original, there could be a negotiation - based solution in the alternate ending. Also, the emotional tone of the story could be different. If the original ending was bittersweet, the alternate ending could be more optimistic or more despairing depending on how the story is rewritten.
There's a chance it could be different. The anime might want to surprise the audience or adapt the ending to better suit the medium of animation. But we'll have to wait and see.