What just happened in the 129 chapter..I'm confused??

I’m curios too.. I think I need to re-read the chapters..

The Eldians and Marlians are trying to get to Eren to stop him from destroying the world while the Jeagerists are trying to stop them because they believe that if Eren is stopped that the world will destroy Paradisa like they've been trying to do out of the fear Marly put into the world of Eldia.

Yes like Super Anime Fan said, both Eldians and Marlians teamed up to try and stop the Jeagerists from "the rumbling", or the titans destroying and wiping out Paradis Island. Chapter 129 was just the Eldians and Marlians trying to escape by ship so they can go to the island Azumibito suggested early in the chapter. They will fly out from there and hopefully catch Eren in time before he annilates Eldia any further. The Jaegerists (floch and them) are fighting with the Eldians and Marlians, trying to stop them from leaving so they can't get to Eren. The end of the chapter shows how the Jaegerists failed and the Eldians and Marlians escaped.