How to Create a Rolling Summary Page that Automatically Updates from a Data Table

So let's try this. In Summary sheet.

In A6 this ARRAY formula.

=INDEX('Data Sheet'!$A$3:$A$3000;SMALL(IF('Data Sheet'!$A$3:$A$3000>=TODAY()-3;ROW('Data Sheet'!$A$3:$A$3000)-2);ROW('Data Sheet'!A1)))

Copy down.

In B6

=SUMIF('Data Sheet'!$A$3:$A$3000;$A6;'Data Sheet'!B$3:B$3000)

Copy down and across.