the open beta version was changed in away that epic loot is broken. there is an issue in the mods github repository
https://github.com/RandyKnapp/ValheimMods/issues/408

but the author said

> Im hoping when Mistlands fully releases this will be updated. For now due to a lot of changes of locations for references in the game code, this mod wont work on ptb.

so seems like he will/can not release a version in the near future to work on open beta :(