If you have one big file now you can use org-roam to create nodes for the relevant sub-heading which can be linked to from elsewhere. These nodes can eventually be moved to their own files when you need.
You may also find the roam ref feature useful for external references/documents.
org-roam can do what you want.
If you have one big file now you can use org-roam to create nodes for the relevant sub-heading which can be linked to from elsewhere. These nodes can eventually be moved to their own files when you need.
You may also find the roam ref feature useful for external references/documents.