Question about sorting by date

[alexmahan]

Hi,

I'm using supersort to try and sort the entries on this page:
https://catrionajeffries.com/artists/valerie-blass/exhibitions

The entries are a combined array of objects. I'm outputting each date into a data attribute on each exhibition:

I would like to order these by most recent date to oldest on the page, but I haven't figured out a way to do this yet.

Have tried various combinations of passing the date into the sort function, but nothing has worked.

{% set sortedExhibitionEntries = combinedExhibitionEntries | supersort('rsortAs', '{exhibitionDate.first.date|date}') %}

{% set sortedExhibitionEntries = combinedExhibitionEntries | supersort('rsortAs', '{{object.exhibitionDate.first.date|date}') %}}

{% set sortedExhibitionEntries = combinedExhibitionEntries | supersort('rsortAs', '{{object.exhibitionDate.date|date}') %}}

I've tried it with and without the date filter, all sorts of other syntax, but it never seems to properly sort by date.

Wondering if anybody might have any insight into the proper syntax here? exhibitionDate does exist for each object, as evidenced by the data attribute in the above screenshot.

Thanks!