I'd make it binary-like, like another commenter said.
Change 3 to 2+1, 6 to 4+2.
8 takes the current 6, and 7 becomes 6+1, 9 becomes 8+1 (current 7). That also gives you hex digits to work with for free, each symbol could store up to FFFF.
It wouldn't change a lot, just removes the downstroke from 3. Of course, 4 bits is an arbitrary choice, one could keep the current 5 bit/segments as well, but not much is needed to normalize it to 4 bits, which is interesting in itself.
I feel like there's a missed symmetry here though and almost symmetrical things are like a wobbly tooth in my brain.
The right line appears at 6, but if you added that at 5 you could repeat the pattern you did for 1-4 for the horizontal lines, which it almost does. 7 and 8 are 6+1 and 6+2.
https://imgur.com/a/NE36rIW