Every couple years, I'll adjust my doodling habits to a set of patterns based on a simplification of the Palmer method. This simple doodling practice has given me the best handwriting at just about every place I've worked in the past ten years.

Draw two horizontal lines about half an inch apart and in the space between them doodle one of:

+ continuous clockwise stream of overlapping circles (imagine you flattened a slinky)

+ continuous counterclockwise version of the above

+ continuous line mountains/valleys (draw an N that becomes an M that keeps going and has tons of peaks)

Repeat.

The first time trying it, most people will find it freakishly difficult to do smoothly and consistently. That's because your fine-motor eye/hand control circuits aren't tuned for these motions which are are the basis functions for all western language penmanship. If you start doodling these figures when you're bored on zoom, your penmanship will magically improve, not because you learned penmanship but because you enabled your fingers to do what your brain is telling them to do.

This will also help you have better penmanship on a whiteboard, but in-office whiteboard writing involves more large muscles as well, so it doesn't hurt to also doodle on a whiteboard this way once you have the fine-motor controls tuned up (the fine-motor remains the most important, even on a whiteboard, so starting with pen and paper doodling will get you where you want to go fastest for either format).