what is the state of the art now, that runs on-device? the article didn't mention the Q$ family, but I haven't found anything better than that plus mixing/co-judging with a dynamic-time-warping based approach

I found that AI can even decipher Suetterlin! Oh well, so much for my secret handwriting.

I tried to search for Q$ but google returned no results. What is it?

For my handwriting, the ParaGraph engine inside Evernote worked perfectly. I believe it's the same system that the US postal service uses.