Filter for Elementor Loopgrid

I’ve inherited a site that is running Events Manager, and to make it short, the site is an entire mess, the theme is old and doesn’t have a license anymore.
I’d like to rebuild the site with Elementor, but sorting the events by date seems to be impossible? I have a working filter on base of a custom field on another website (which uses ACF). It simply takes the respective custom field and orders it by date.

Here I’m not entirely sure what the custom field even is. The documentation says that attributes and custom fields are somewhat the same, but I’m wondering why there is a difference then, and if the attribute #_EVENTDATES is the same as a custom field. It doesn’t work in the filter, nor can I display it simply by choosing the meta key for any elementor widget – which I have done on many other sites. It only works when put in the shortcode.

Does anyone know what the actual custom fields are/how to integrate this into a loop grid?