Nice.
I believe this is somehow related to this thread:
On that thread the idea is to apply a bm25 after to reinforce some properties, but that “intentional bias” could also be extended to other late reinforcement other than a bm25, like in your case, taking into account a datetime property.
This is a good feature request. Do you mind opening one in our GH so we can keep track in our roadmap?
Thanks!