Setting a reminder for a specific day rather than date

In Reminders app:

1. Add new reminder (choose your title) to store it on your iCloud account or locally “On my Device”.
2. Tap “i”.
3. Enable Date and select last Wednesday of the current month (e.g. July 28, 2021).
4. Go to Repeat > Custom:

• • Frequency: Monthly
  • Every: Month
  • On the… last Wednesday

In Calendar app:

1. Add new eventy (choose your title) to store it on your iCloud account or locally “On my Device”.
2. select date last Wednesday of the current month (e.g. July 28, 2021).
3. Go to Repeat > Custom:

• • Frequency: Monthly
  • Every: Month
  • On the… last Wednesday

1. Choose when repeat should end.

You'd need to use an app that has more robust recurring event functions. Try Week Cal.

Glad to hear they've got that working since the last time I checked.