A few notes:
1. It's not Medium burnout per se, it's more along the lines of cost-benefit imbalance. Five stories a week is far too many. I can speak from experience. Reduce it to just one story, but make that one story damn good.
2. Ditch the Medium groups, just focus on your writing, and maybe your publication, if you want to keep it. Medium groups are a distraction and the returns (if any) are negligible.
3. How much money you make on Medium is relative to what you consider much and how solid your writing is. The Medium gurus are wrong. I have been here for over 10 years, and the one consistent value that hasn't changed on Medium is that quality content wins, no matter how the platform changes. One great story is worth far more than five mediocre ones (not that there's anything wrong with mediocrity).