Filter Query to have OR-ing of values having null

[tanvi-cota]

Currently, I am trying to let user select options for the filters.
Consider options 1, 2, 3, 4, 5, null.
When user selects - 1, 2, 4; the filter dimensions are set using equals
But when user select - 1, 2, null; we do have have simple way of calculating this.
I know, we have notSet but thats only for null, and not contains.

Expected Solution -
Equals should honor null

Currently implemented -
Not Equals with the other remaining options