Apart from the general question above: 
I visually checked the undone reverts and current display of seagrass in OSM (26.6.2023 18 hrs UTC). So far I found only one instance, where an older version of an anchoring area (https://www.openstreetmap.org/way/588629274) now incorrectly overlaps the protected seagrass (https://www.openstreetmap.org/way/1003725381). I will leave few days distance to the revert and undo process and then correct this way 588629274 manually. 

Great how you managed to undo the revert for the seagrass, which existed in OSM before this changeset. The initial visibility of the  seagrass in OSM illustrates the purpose of the seagrass tagging and will lay ground for future careful work in OSM on seagrass and the nature of the seabed. Thanks to SomeoneElse again. Jo