Relative Date Slicer to allow full months in the past and partial current month

Today you have only two options to filter months in the page level, with the relative option

Assume we are now in the middle of Nov. 2020 and I want to show the last 6 months dynamically.

When I select Last 6 months, I get all the data starting from November 15th back -180 days. It is not covering half of January...

When I select last 6 *calendar* months I do not get November at all.

There must be a way to really filter on last 6 months and not let the filter translate months to days...