I would say that with the gesture and the stylisation of the primary shapes you have definitely hit the nail on the head. May I suggest you try to make a few quick sketches, without worrying too much about completing the anatomy for the time being, concentrating only on gestures and structure? That way it becomes much easier to deal with more detailed drawings.            At least, I found myself understanding the way horses move much more quickly by doing this, rather than dwelling on individual photos for a long time. I'd say you already know the principles, the drawings in which you emphasise gestures and structure are correct (third, sixth and eighth), so why not have a bit of fun without worrying too much about producing a finished work? :)

Another horse! Tried really hard to get more anatomy in there and make the forms sit better in 3D space.

Another ugly horse incoming! I like how I was able to show the momentum in the gesture but yeah beyond that it needs work. Gotta work on proportions and eventually anatomy. And rendering hair better. And basically everything xD Stuff that makes me implode to think about right now. Taking this massive learning journey on one chunk at a time.

The main thing i can point out is the structure, what could help you is using 3D shapes to do the first draft

This is just a suggestion, but doing 100 horses might not be the best idea, your drawings do have pontential but you're lacking a foundation. Animal anatomy is studied after human anatlmy because, even though they're different, the skeletons of living creatures have many similarities, so if you get good first at human anatomy you'll understand afterwards animal anatomy relating existing concepts: joints, ribcage, etc. Drawing many horses righg now is reinforcing mistakes, also, you can become better at drawing animals without anatomy knowledge, with perspective and sketching techniques you could get a decent initial structure gor those horses