First off, plugins - EssentialCmds is no longer supported, please move to Nucleus. Nucleus includes everything EssentialCmds can do, and more. If you need help doing so, you can join Nucleus’ support team here - we will be glad to help you. That SpongeForge is not the latest - you can get the most updated one here. Grief Prevention works best with LuckPerms from experience, you can consider moving to this permission plugin if you want it to work best with GP.
As for the actual crash, it shows that a world file is corrupted. Try deleting your level.dat first. Did you make this world with EssentialCmds? If so, it could explain the issue, since that plugin manages worlds… and in this case, it is outdated to the point that it could cause problems with latest SpongeForges.