I’ll preface this all with the disclaimer I have no smart / powered blinds yet. Just a tinkerer who has some ideas to try until the Bond staff get a chance to weigh in.
I’m wondering if setting the REPS part of the signal via API could help a little to send 20 repeats of the single command to have less “jerky” motion.
As another weird workaround possibly, you could train a new “ceiling fan” device in the Bridge with manually recorded button presses of your OEM remote, for hold to dim (lower shade), hold to brighten (raise the shade).
Remove all the other unnecessary commands and see if it works in the Bond app.
Now, making it work in the API / Indigo might be a little more dramatic; previously I had used the older options available in an earlier version of the API to start a looping dim / brighten cycle via an integrated in-wall keypad, which was halted by pressing the button again whenever I liked the light level.