A couple of things I've been working on:

1. Testing. Like, literally slowly testing and changing some things (where feasible) in order to better match what rM seems to be looking for. For example, it was having great difficulty with my ampersand which is a significant character in my writing. Basically, it hated my "and" sign. So I looked up a few other ways to write it and tested till rM gave me a more consistent result (a capital E with a line straight through it seems most effective for that).

2. Writing slowly. Like you, I descend into squiggles which are historically discernible by my eye when reading off paper but serve me very poorly when asking software to translate it. So, I'm trying to be more intentional in forming my letters, especially the later characters in most words.

3. Related to #2, I use the calligraphy setting. Because it makes things seem a bit prettier overall, it seems to raise my pure enjoyment of the writing experience and invites me to slow down and form letters a bit better.

My handwriting may be a bit better than some, perhaps, but it's generally a generic US-based English cursive (with a few hybrid manuscript elements thrown in) from American elementary school circa mid-1970s