Based on this Microsoft Guide, (which could of been written better IMHO), when you want to add a list of "co-owners" into your Power Automate project from a SharePoint list....
- Go into your SharePoint site and on the top right click the members link (as shown below), and add your members as editors for the site.
- Also, once in your list, go to list settings -> Permissions for this list, to then confirm that these editors also have access to edit on your custom list.
The key thing that gives it away from the Microsoft Guide I provided above is when Microsoft said...
"Now all users that have read/write access to the Document library automatically have permissions to run the flow from the Flow menu in SharePoint."
Once you confirm that the users have the proper permissions in your SharePoint Site and List, then go back into Power Automate to add the list as you originally described. Hopefully this is a start for understanding how the "co-owner" process works in Power Automate.
