Try this below Power query script to achieve your desired output-
let
Source = Excel.Workbook(File.Contents("D:\WORK\R&D\Book2.xlsx"), null, true),
sheet1_Sheet = Source{[Item="sheet1",Kind="Sheet"]}[Data],
sheet2_Sheet = Source{[Item="sheet2",Kind="Sheet"]}[Data],
#"Unpivoted Columns" = Table.UnpivotOtherColumns(sheet1_Sheet, {"Column1"}, "Attribute", "Value"),
#"Unpivoted Columns2" = Table.UnpivotOtherColumns(sheet2_Sheet, {"Column1"}, "Attribute", "Value"),
#"Pivoted Column" = Table.Pivot(#"Unpivoted Columns", List.Distinct(#"Unpivoted Columns"[Column1]), "Column1", "Value", List.Sum),
#"Pivoted Column2" = Table.Pivot(#"Unpivoted Columns2", List.Distinct(#"Unpivoted Columns"[Column1]), "Column1", "Value", List.Sum),
#"Removed Columns" = Table.RemoveColumns(#"Pivoted Column",{"Attribute"}),
#"Removed Columns2" = Table.RemoveColumns(#"Pivoted Column2",{"Attribute"}),
#"Demoted Headers" = Table.DemoteHeaders(#"Removed Columns"),
#"Demoted Headers2" = Table.DemoteHeaders(#"Removed Columns2"),
#"Demoted Headers1" = Table.DemoteHeaders(#"Demoted Headers"),
#"Demoted Headers12" = Table.DemoteHeaders(#"Demoted Headers2"),
#"Replaced Value" = Table.ReplaceValue(#"Demoted Headers1","Column1","Sheet1",Replacer.ReplaceValue,{"Column1"}),
#"Replaced2 Value" = Table.ReplaceValue(#"Demoted Headers12","Column1","Sheet2",Replacer.ReplaceValue,{"Column1"}),
#"Replaced Value1" = Table.ReplaceValue(#"Replaced Value","Column2","Sheet1",Replacer.ReplaceValue,{"Column2"}),
#"Replaced2 Value1" = Table.ReplaceValue(#"Replaced2 Value","Column2","Sheet2",Replacer.ReplaceValue,{"Column2"}),
#"Replaced Value2" = Table.ReplaceValue(#"Replaced Value1","Column3","Sheet1",Replacer.ReplaceValue,{"Column3"}),
#"Replaced2 Value2" = Table.ReplaceValue(#"Replaced2 Value1","Column3","Sheet2",Replacer.ReplaceValue,{"Column3"}),
#"Appended Two Sheet" = Table.Combine({#"Replaced Value2", #"Replaced2 Value2"})
in
#"Appended Two Sheet"
Input sample data from 2 sheet-
Final output in Power BI-