Ooooh, I think I have experiences and strategies to share about this
I'm pretty much like you right now, getting better at art but only having a pile of sketches to show for it. My mind is also very scattered and likes to jump from project to project, from idea to idea, the same way a squirrel jumps from tree branch to tree branch.
Just about recently I figured out things that work for me. I'll share them, in hopes if not all at least some of them work for you too
For me, it's very important to
visualize progress. I can't ask to my mind to keep track of how many days have I been doing X on top of everything else it does!

I tried journalling about it, but for me it didn't work because I don't tend to read my past journal entries. I read that the key to many things is to
make them very obvious and simpleSo I began putting
post-its on my walls. One
post-it stating the habit I am trying to form, and next to it I add a post-it everyday if I accomplish the task related to the habit: kinda like a progress bar in a videogame

These post-its are blank, easy to take down and interchange.
The key to this is to
start small. If what you want is to read more, read one page a day. If, in my case, I want to animate, the bare minimum is always one frame. For "static" art, it could be one "step" of the process (sketch-lineart-flat colors-rendering-backgrounds-etc...). This doesn't mean you are limited to just "one", you can always do more if you feel like it

But at least for me, this works, because
1- Once I get around to doing one I end up in the same state of mind that makes me want to keep at it, and instead of just one frame I end up doing a good chunk of the animation
2. If it's one of those days where you aren't feeling as proactive (specially taking into account you're recovering from injury!), one is enough to earn you that one post-it, that one point in the progress bar.
If you manage
two weeks in a row (14 post-its), you can
crank the lever a little higher: two pages. Two frames. Two steps of the art-making process.
If you skip a day, you take down all the "progress-bar" post-its and start again. It was a bit hard for me to do this when it happened to me, but it was good because I understood
it didn't mean I failed. It meant I'm not ready to take it "to the next level" just yet. If you try to start big and do a lot in too little time with no flexibility, you're setting yourself up for disappointment. Or at least, that's my experience and I hope I'm not the only one

.
But if you start this small, you slowly convince yourself that you can do stuff consistently, and you're achieving things along the way
This is something I adopted about last month, and I think it's my best "system" to get myself to do things so far. I'm two thirds/halfway into my animation project thanks to it, among other good habits

It's cheap and it won't ruin your walls
I have
other systems that compliment this one, such as rewarding myself by playing little bits of videogames as a reward
(more about that here) and gamifying the habits as well (when I mean "level up", i kinda mean it like a game, I have also a little creature drawn on each "habit post-it" that I draw "evolutions" on everytime I get two weeks in a row on that specific habit)
I don't know if this is the kind of answer you expected, but I hope it helps! I'm very passionate about self-improvement and I like sharing my strategies in hopes it helps other people, as well