Mongo return what inputs don’t match for $IN

Is there any way for Mongo to return some indication (flag, field, etc..) for if an input in a $in does not match any docs?

Please see my Mongo Playgrond

That successfully just returns all odd documents.

How can I have some indication that the evens were not found?

I’d like to do this within Mongo itself. I get I can iterate through the results in JS and perform a diff.

Fwiw, I this $in will actually be the first stage of a $match in an aggregate . So maybe I can use something like addFields for the unmatches.

Thanks!