The config screen works and values can be changed without issue, however, these changes are not saved to the config so everything resets when the game is relaunched. I don't know if it's normal or not, but my config file is nothing but "{}".

This is very probably an issue that exists because I'm using Sinytra Connector to run Sonance on a Forge instance, but in the off chance that it isn't (or that it is but could somehow be fixed on your end) I figured I'd make a post.

Update your sonance, this is fixed in a later version of the mod.

It seems like the version uploaded for Sonance 0.2.1 is incorrect, the file is still called Sonance 0.2.0. I checked both CurseForge and Modrinth, and neither newest version for 1.20.1 fixed the issue.