Two charts with dynamic dates

Hi, stuck with the following;

I have two YTD charts on the same page displaying the same measure that spits out a count value on a weekly axis. The first chart shows the selected year via a slicer but the other needs to show for the year previous to whatever is selected.

I've tried doing this by making two seperate measures and minuplating the dates based on the slicer selection but this won't work for various reasons. My other solution which isn't working is to try and add something to the filter, like a switch of 1 or0...1 being the year I want and 0 being the years to not show but I can't figure this out and get it working.

I thought I could create a calculated column in my date table that would give a 1 or 0 based on the selected slicer? I.e.

PY = 
Var _Selected = SelectedValue(Slicer)  //2023 for example
Var _PY = _Selected - 1
RETURN
If('date'[year] = _PY,1,0)

This just returns 1 for every row 😞

Any ideas? 

Thanks,
 Ben