I'm in no position to advise, but my experience may contain a clue, if anyone can interpret it.
The facts: I joined in July. I published maybe 30 items before getting too busy with school. The last item came out about 2 months ago.
Only 3 articles ever reached $10, but those 3 have kept on paying. My monthly earnings have been $3, $104, $1733, $351, and $1325 in November, when I published nothing.
I have high hopes of writing more articles when the semester's over, and I hope eventually to earn $2-3K/mo writing part-time while I teach somewhere and work on my novels, but in the meantime, I find Medium nothing short of baffling.
I wish you luck figuring out what's going on. I'm happy with how this platform's treating me, but it flies in the face of all the advice about publishing daily being the only way to make money here.