The Problem

I am trying to combine Sheet1 & Sheet2 into Sheet3 sorted by timestamp, but I am unable to adjust the columns so they match between both datasets. Is this even possible with using formulas, or is my only option Google App Scripts?

My Attempt

=query({Sheet1!A2:F;Sheet2!A2:F},"WHERE Col1 is not null ORDER BY Col1")

I have also tried other methods using helper columns, but that did not work very well either.

Spreadsheet: