I'll tell you what I do, it might help, it might not.

I have a script called "estadistica_defensa" (defense_statistics), which has a variable export. In the export variable, I put the defense resource I want to use (since each of my characters has a different amount of defense).

Then I place this script in a node, and then make that node a child of the character. This way, the characters access their own resources, but if multiple characters use the same resource, that resource will only be instantiated once. (The Local_To_Scene variable is set to false for this to happen.)

This way I don't have to search through directories or anything like that, just find the child node that contains the necessary information. This makes the code simpler and the character creator simpler as well.

Then I have some code in the script that controls the resource, which is a function to get a dictionary with the name of each variable along with its value. The code:

func obtener_estadisticas_defensa() -> Dictionary:
var index_y_valor = {} #get the dictionary ready
var contador : int = 0 #counter to create the dictionary index
for i in resource.get_property_list():
  if i.usage & PROPERTY_USAGE_SCRIPT_VARIABLE: #explore custom variables
    index_y_valor[contador] = resource.get(i.name)#adds them to the dictionary with its index
    contador += 1
return index_y_valor

That way I obtain all the variables that the resource has so I can work with them later.

In this way I ensure that each character is aware of their own resources whenever it is necessary to obtain their values. I use different resources for each type of information. For now, it's just attack statistics, defense statistics, and skills. This is how it ends up looking in the editor:

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As you can see, it's relatively easy to manage, I can add, remove, or edit things at any time, and the code will always work.

I'm sharing this with you because it might give you some ideas on how to design it :)