Great news!! my plants are coming back. My magical trick? I stopped watering them.
Yes, it appears that I was overwatering. I stopped watering for several days to allow the soil to dry out. I picked off the dead leave and left it alone for a couple of days. After that, I watered from the bottom like I was supposed to be doing. I can’t explain why I spent all that time making these self-watering containers and then watering them like normal.
The moral of the story, trust the system!!