Hi!
The Looper Provider sorting options for the Posts does not allow dynamic dates, from what I see.

In my example I need to sort Modern Events Calendar’s events, based on the Start date of the Event.
There is a Custom Key for the start date: mec_start_date. It returns results like this: 2020-11-10.
I believe that we should be able to sort posts based on custom keys that are returning dates.
PS: in my other thread, I am reporting that this key is not returning dates in the proper format.