Previous Year calculation based on date slicer -- multiple date / discontinuous date selected

Hi, 

I have a project on comparing the sales data in current year and previous year, and here are my DAX codes for the measures:

TotalSalesCY = SUM (Sales[Amount]) 

TotalSalesPY = CALCULATE ( TotalSalesCY, SAMEPERIODLASTYEAR(Date[Date]))

I have a slicer using the date table date column named "Date[Date]", and i set it to "select single item" only, it works well.

howevern, my user would like to have a date slicer with more functions: 

1. select multiple dates; 

2. select discontinous dates, e.g. Jan 2026 and Apri 2026, don't select Feb and Mar; 

3. the selected dates could be in different years, e.g. Dec 2025 , Feb 2026, without Jan 2026. 

My current Dax solution worked on multiple date selected when they are in the same year, but on condition 3, when 2 or more dates in differernt year were selected, my CY and PY sales measure both failed with the error msg below: 

And also not work on "DATEADD( DATE[Date], -1, year), same reason. 

Then I tried to grab the dates one year before selected by 

but on Returning this / use it in a calcalate func it also failed. 

If the dates selected are not contiguous , the daterange by min(date) to max(date) also won't work.  

I am looking for other solutions on this, and also wondering why my CY sales also failed on it. 

Thank you!