Exclude dates in Dashboard

Hello,

I am trying to exclude a specific month from my Dashboard data, while still allowing people to use date as a filter.
(I.e. exclude December data, while allowing people to filter on any date they want, ex: past month or past year).

I tried in the settings, or by adding a specific date filter on the tab, but I wasn't successful. I was thinking of creating a new embedded data with 0/1 value (0 = December data, 1 = rest of the data), and add that new variable as a locked filter.

Any other solution you would recommend?

Thanks so much in advance!