Allexcept - Remove slicer

Count APF Status_Site_AT Filter =
CALCULATE(COUNT('lead'[Status 2]),
  ALL(),
  'lead'[Country construction site]="Österreich",
  VALUES(Datum[Date]))

Well, the question was to remove all filters, and there is no real difference between row/column context and filter context.
There are two ways of fixing this
1) expand the current measure. The current measure uses ALL() to remove all filters, and then VALUES(Datum[Date]) to re-apply the dates in the active context. You can simply add that column in there (example below, adjust if the value is not from that table, but from a dimension table).
2) Alternatively, do not use ALL() but expand the context only for the slicers/filters you want overriden.

Count APF Status_Site_AT Filter =
CALCULATE(COUNT('lead'[Status 2]),
  ALL(),
  'lead'[Country construction site]="Österreich",
  VALUES(Datum[Date]),
  VALUES('lead'[Status 2])
)

Count APF Status_Site_AT Filter V2=
CALCULATE(COUNT('lead'[Status 2]),
  ALL('lead'[Country construction site]),
  ALL('tableA'[column x]),
  'lead'[Country construction site]="Österreich"
)