Same Week last Year Flag

Some good news...

I manipulated the code you provided in your most recent comment to be:

week_and_year = YEAR('FV_SALES_BASE'[Testdate])+WEEKNUM('FV_SALES_BASE'[Testdate],1)*10000

TestColumn = 
var _value_1 = 'FV_SALES_BASE'[BRAND_VALUE]
var _value_2 = 'FV_SALES_BASE'[week_and_year]
var _value_3 = 'FV_SALES_BASE'[week_and_year] - 1
var _value_5 = CALCULATE(COUNT('FV_SALES_BASE'[BRAND_VALUE]),FILTER('FV_SALES_BASE','FV_SALES_BASE'[BRAND_VALUE]=_value_1),FILTER('FV_SALES_BASE',FV_SALES_BASE[week_and_year]=_value_2))
var _value_6 = CALCULATE(COUNT('FV_SALES_BASE'[BRAND_VALUE]),FILTER('FV_SALES_BASE','FV_SALES_BASE'[BRAND_VALUE]=_value_1),FILTER('FV_SALES_BASE',FV_SALES_BASE[week_and_year]=_value_3))
RETURN
SWITCH(
    TRUE(),
    (_value_5 <> BLANK() && _value_6 <> BLANK())
  ,"Y",
    "N"
)

I then added an additional date column that filtered to only the past 2 years:

Testdate = Dateadd('FV_SALES_BASE'[DT],2,year)

By doing this, I was able to achieve accurate 'Y' and 'N' for the year of 2022. In theory, I could do this for every year but it would add an additional 12 columns total to my table I believe (as I think I would need these 3 columns individually for each year, going back to 2019.) 

This is a potential solution, but far from ideal. Are there possible workarounds to this problem that I could utilize?