Filter based on current date

So I have a datatable with dates in the format yyyy-MM-dd. I checked the datatype for the date column and it is “System.Object”.

The first step i want to do is to remove dates based on the current date.

For example today is the 2020-10-21. I know need to keep all dates previous to 2020-10-21 and all the way to 30 November.

If the date was 2020-10-20 then I would need to keep all the dates previous to 2020-10-20 but only all the way to 31 October.

The breakpoint day for every month is the 21st.

How can I achieve this, with the filter data table or for each row activity?

If I need to add more information I will gladly do it.