Referencing the correct object in a formula

I have macro that performs a reformat of a collection of sheets that are contained in a single workbook.

Option Explicit

Sub ConsolidateReformat2()

Dim sh As Worksheet
Dim LastRow     As Long
Dim FirstSht    As String


For Each sh In ActiveWorkbook.Worksheets

    FirstSht = Sheets(1).Name
    
    'Piecing together a macro
    sh.Sort.SortFields.Clear
    sh.Sort.SortFields.Add Key:=Range("R:R"), _
        SortOn:=xlSortOnValues, Order:=xlAscending, DataOption:=xlSortNormal
    
    With sh.Sort
        .SetRange sh.Range("A:V")
        .Header = xlYes
        .MatchCase = False
        .Orientation = xlTopToBottom
        .SortMethod = xlPinYin
        .Apply
    End With
    
    sh.Range("C:C,E:E,F:F").Insert Shift:=xlToRight
    LastRow = sh.Cells.Find("*", Cells(Rows.Count, Columns.Count), _
        SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
        
    sh.Range("C2:C" & LastRow).FormulaR1C1 = "=RC23 & ""-"" & RC1 & ""-"" & RC4"
    sh.Range("F2:F" & LastRow).FormulaR1C1 = "=IF('" & FirstSht & "'!RC5>=1,""Yes"",""No"")"
    sh.Range("H2:H" & LastRow).FormulaR1C1 = "=RC2 &"" ""&RC7"
    sh.Range("C1").FormulaR1C1 = "PRODUCT_CODE"
    sh.Range("F1").FormulaR1C1 = "AVAILABLE"
    sh.Range("H1").FormulaR1C1 = "PRODUCT_NAME"
    sh.Range("L1").FormulaR1C1 = "PRODUCT_COST"
    sh.Range("P1").FormulaR1C1 = "WEIGHT"
    sh.Range("J1").FormulaR1C1 = "PRODUCT_DESC"
    
    
   

Next sh
 
End Sub

however the problem is with column F and this code

 FirstSht = Sheets(1).Name

sh.Range("F2:F" & LastRow).FormulaR1C1 = "=IF('" & FirstSht & "'!RC5>=1,""Yes"",""No"")"

instead of applying to each individual sheet the FirstSht is referring to the very first sheet in the workbook instead of carrying out the operation in each worksheet of the formula. How would I change this so that the first sheet index is not being used in all the subsequent sheets but rather the columns that are specified in the formula?