According to your description, you want to show TODAY() on the bar chart as the basis for judgment, showing the values of the past 6 months and the next 6 months. Right?
Here are the steps you can follow：
(1)This is my test data:
(2)We can click “New measure” to create a measure used to override the Y axis: “value”
value = CALCULATE( SUM('Table'[test]) , 'Table'[Date] < EOMONTH( TODAY() ,6)+1 && 'Table'[Date] >EOMONTH(TODAY(),-7)+1)
(3)We can put the [Date] in X axis of the bar chart (Keep the year and month) and we put the [value] measure in the Y axis:
If this method does not meet your needs, you can provide us with your special sample data and the desired output sample data in the form of tables, so that we can better help you solve the problem.
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly