This requirement is flexible to some extent. The primary goal is to associate a document in O365 to an Opportunity in Dynamics 365. This is similar to how D365 tags emails to opportunities.
If I could put a file in a particular Document library (or in a folder with metadata or a file with some D365 opportunity metadata), I want to connect this to an D365 Opportunity as a link.
Can this be done with a Power App or a Logic App? I need to deploy this for the entire site collection.