Hot to get data from previous year in Google Looker Studio (Data Studio) when using Supermetrics (Apps Script Add-on) connector

Question

I'm pulling data from Google Analytics for 150+ accounts, using Supermetrics for Looker Studio.

Now I want to create a table with Y/Y data, e.g:

Date	Date_last_year	Revenue	Revenue_last_year	Cost	Cost_last_year
1 dec 2023	1 dec 2022	1000	980	500	550

I've added a calculated field to the data source: Date_last_year = DATE(DATETIME_SUB(Date, INTERVAL 1 YEAR)) which gives me the correct last year's date.

However, when I try to blend the data source with itself, doing an inner join on date_last_year and date, I get no data.

I'm guessing the issue is that I can't add Date as a dimension under Date Range

This option shows up if I e.g. use a GA view as source data:

Is there any way to make this work using Supermetrics for Looker Studio?

I don't have the option of pulling the GA data into e.g. BigQuery, so I need to find a solution using the existing setup :(