I’ve turned this into a new topic, as it seems a separate subject.
I’m not sure if a deleted note can be recovered. For this you can best reach out to Asana support: How to contact our Support Team ✉
I’m not sure if that’s wise. While Asana is meant for Work Management people usually have a separate tool for storing files. Usually something like Google Drive or Sharepoint.
Using a sharing link tends to work well in my experience.