You may wish to further elaborate your requirement to assess feasibility and then possibly community could respond.
For example, is the data in another table accessible to the AppSheet app? Are you always looking for last four weeks data and or desire to have some filtering on the fly but in that case how you expect the filtering parameters to be decided. What do you mean by specific set of rows? By snapshot do you mean SNAPSHOT() function in AppSheet? When you mention “before displaying it”, do you mean before displaying it in PDF report or displaying it in a specific app view?