Harmony X is a mod

You need to have a "clean" install.

To do this you need to..

Uninstall game

Go to folder manually in steam - steamapps - common - valheim and delete the entire folder

Reinstall game and check operation before you add in any mods.

The problem is an uninstall will not remove files the game did not put in, so you must manually delete the install folder to clear it out.