PixieBrix is not compatible with Vue3, so if you're using the @pixies/vue/set-values brick, you'll need to migrate to the Set Input Value brick @pixiebrix/forms/set.
If your mod was built in the Page Editor, you can make the change there, otherwise you'll need to head to the Advanced: Workshop to find the YAML file for the mod, and make the following changes.
What you need to do
Go through your YAML file and, for every instance of:
@pixiebrix/vue/set-values
Make these changes (detailed walkthrough below):
Update the brick ID
Add rootMode: document
Add dispatchEvent: true
Restructure the config section to use inputs: with selector and value pairs
No other logic needs to change. The values and selectors you already have remain the same. Only the structure and brick type need to be updated.
Finding your existing Vue brick
In your YAML file, find any brick that looks like this (your current version):