How to create historical data for measures

Hi,

I have a power bi desktop file that contains some measures. This file also has a table which contains the column "Products" and these measures calculate a value per product. The data used to calculate these measures is not a historical dataset, so I can only get a real time value for these measures.

I want to be able to have a historical dataset that gives me the value of the measures per product at the end of each month, and ideally for this to be an automated process - end of each month, the new values get appended to the historical dataset. I want the historical dataset to look something like this:

(Date = the date the row is recorded)

How should I best approach this? (Happy to use external tools like excel, power automate, etc)

Thank you!