Any form of help is welcome

Hi there, for a new design idea i’m looking for a way to have a massive (200x200 as a size idea :slight_smile: ) raised chunk about 30 blocks higher then water level next to a water sourch. Top of the chunk has to be grass layer.

Just wondering if there is a mod out there that allows me to alter a map to create this. If only the grass and dirt block was in the game already i could make it between some mountain parts. But seeing that will be out there for a while i was wondering.