There were reports I read earlier that part of the unsticking process was pumping fuel and ballast water around to remove as much weight as possible from the bow of the ship. It's probably unbalanced the ship a bit and they're just waiting to get to the lake to pause and fix it to allow shipping to resume as fast as possible.
[1]: https://english.alarabiya.net/News/middle-east/2021/03/29/Su...
[2]: https://www.aljazeera.com/news/2021/3/29/ever-given-turned-8...