I have spent forever (it seems) trying to crack this nut. My preference at this point is to write on paper, then run an action in Drafts that opens up Prizmo Go (their paid handwriting recognition is really good), then dumps the recognized text in Drafts. Then I can run actions from Drafts to particular Devonthink folders or Obsidian (I have a great Zettelaksten template in Drafts, and so a different Drafts action runs the same sequence above, but places the Prizmo text into a formatted Draft page).