It is trivial to add Drafts tags as hashtags when exporting. In fact there’s a [[hashtags]] template tag that can be used in Drafts actions to include tags in #hashtag format (more on templates).
That said, this won’t help you to tag items in Apple Notes. Best as I have been able to tell from testing in the new release of Notes, it only recognizes and tags a note if the #hashtag is typed into the note. If you paste in text with tags, or use the Shortcuts or AppleScript methods to set the content of a note, it ignores those tags. They appear as text, but it does not actually treat them as tags.
Apple would have to update Notes to support tags better to make this useful.