Reloaded UI and now this happened, cannot use Questie at all anymore tried reinstalling and deleting folders.

Questie: [ERROR] Error during initialization! Interface/AddOns/Questie/Database/QuestieDB.lua:925 attempt to index local 'startedBy' (a nil value)

Running SoD Classic wow.

Checkout #5333 - the command there will work for you as well.

A proper fix will be included in the next release!