You have uncovered the reason why it is so damn hard to keep writing on Medium. I don’t understand how one month I made a few hundred and the next 3K! They say it’s reading time, but I agree, it would be nice to see how they calculate everything.
Despite the frustration, Medium does pay its writers. I don’t know what the sweet spot is, but if you can keep moving forward, and somehow mute the frustration, you will get to a point where you are paid well.
I’m not saying it’s easy, and I don’t have a magic formula because I don’t know anything about the Medium algorithm. All I know is to keep writing and publishing and improving.
It will happen!