Reporting values with sliding dates using a slicer to define how many days before or after

Hi all,

I have a very simple report: values for each day of the year.

My needing is:

beside the column with the values of the single date, I have to show the values related to a different day, that can be 1 or 2 or 3 or.... days before or after.

That means that the report user should have the possibility, using a slicer, to define "how many days" before or after.

I.E. looking at the value of 15th August, I want to able to show the value of the 12th August, if flagged "-3" in the related slicer.

Tried many ways, many many hours of tentatives without success.

PLEASE FIND PBIX FILE AT THIS LINK:

https://www.dropbox.com/s/5jjvnszhsmgtqsk/Test%20allineamento%20date.pbix?dl=0

Also following image as example:

Thank you all for any help.

Alessandro