Thanks for the post on a read-only solution for notes
I like that your solution runs in the cloud. I investigated implementing read-only by updating the contentClass field, but I could only implement on my Mac
Your unlock process is awkward. I'd prefer a simple unlock of the note instead of:
This will create a duplicate of the same note in your default notebook, which you can edit (title and content only). After you're done with it, add "makemigration" tag to this duplicate, without changing prior tags, and sync. After a minute or so, this duplicate will be deleted and your original will be updated with the content you provided in the duplicate.