A solution to this problem is to add a new column B to your data set that shows if the date in column occurs the desired timeframe. Here is the formula that I would use:
=AND(TODAY()-A2>=180,TODAY()-A2<=210)
The answer will be either True or False, depending on the date in Column A. Next, you need to set up a filter so that you only display dates in Column A where Column B is equal to True. The result will display only those rows where the dates in column A are between 180 and 210 days old.