Adding to the mess of ideas : )
Another possible approach is to set the RG data type to a non-thing, for example number.
Add a custom state to retrieve the list of database things.
Set the RG data source to a list of numbers, of count = 1 higher than the custom state list count.
Inside the cell, set a group of type thing, retrieve from the custom state, item number being the same as the cell number.
Inside the group, you can have elements referring to the parent group’s fields.
An alternative group can be visible when thing is empty, and contain the inputs.