Okay reading over your replies, I think I have a solution. If you build the Count Data Source with how many ever rows you need, just set those values to the number of the row. The count data should be 1, 2, 3, 4, etc. for how many ever loops you need. I can whip up a groovy script to help with this too.
From there, in your groovy script data source, set a date function that takes a NOW timestamp and adds the value from the count data source.
so on the first loop it would be
21.5.2022
but on the second loop, it would be
22.5.2022
(using today's date)
I can provide groovy samples to handle that too.