Quite an impressive workbook.
I apologies at the outset if I did not catch the full gist,
but it feels like part of the issue is that your Groups of campaigns
can't be used in a calculated field:
The specified item was not found.
Instead, I think you'll need to create a parameter that contains all
your group names, and then use a Filter of
Then you can make Dynamic Metrics such as
WHEN "Finding Dory" THEN [Dory CPL]