When adding a custom field of type or it currently does not show up in the "Custom Fields" section of the details pane.

Additionally, to "fill out" these fields you need to go into the / section where they appear in section amongst the other options.

I would like for this functionality to behave more like actual custom fields where they appear in the custom fields list where can be pinned to show that they are a property that needs to be filled in.

Additionally, once linked, if they could show the columns/fields that you want selected similarly to how they already appear in the relationships panel that would be a bonus and hugely benefits the usefulness of these custom fields.

Also I am aware that in the future custom fields are planned added to lists and other objects, so if the functionality of being able to link other object types could be extended to those and show their own custom fields then that would be amazing too.