custom sort predicates for org-ql--sort-by?

Apologies if it's a duplicate -- I searched over issues/prs and didn't find anything existing

I want to sort the results of `org-ql-search` by a "created" timestamp -- in my case it's either a `CREATED` property or just a first inactive timestamp in the outline (e.g. `* [#B] [2022-08-01 Mon 00:38] some note`).
I went through the source code
https://github.com/alphapapa/org-ql/blob/eb5377320fcfd38354d6e9e3e655969ae3c0e052/org-ql.el#L2400-L2436 , and seems that it only supports predefined sorting predicates at the moment?

I'm happy to try and contribute support for custom predicates, just want to double check first that would fit into the library. E.g. I imagine it might have some impact on caching?

I imagine as a workaround I could abuse existing `org-ql--date<` sorting key and override it to extract the `CREATED` property or something like that.
Thanks!