Define the last row for a macro

Good afternoon everyone,

I have been working at this for a while, trying to convert macros that I've used previously to define the last row in a set of data, and I can't seem to get it to work. What I want this to do is to find the last row with data, in any column out to column BZ, in it and define it at the last row to be used in place of "xyz" in the macro attached below. Incidentally, it is probably fairly obvious that I am new to VBA, if you have a suggestion about how to make this macro more efficient, I am open to suggestions!

Thanks for your help!

Private Sub cmdSort_Click()
    
    
    If chkFE = True Then
        For Each cell In Range("BC4:BCxyz")
            If UCase(cell.Value) <> "Fire Extinguisher" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
    
    If chkChem = True Then
        For Each cell In Range("BD4:BDxyz")
            If UCase(cell.Value) <> "Chem" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkFL = True Then
        For Each cell In Range("BE4:BExyz")
            If UCase(cell.Value) <> "FL" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkElec = True Then
        For Each cell In Range("BF4:BFxyz")
            If UCase(cell.Value) <> "Elec" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkFP = True Then
        For Each cell In Range("BG4:BGxyz")
            If UCase(cell.Value) <> "FP" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkLift = True Then
        For Each cell In Range("BH4:BHxyz")
            If UCase(cell.Value) <> "Lift" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkPPE = True Then
        For Each cell In Range("BI4:BIxyz")
            If UCase(cell.Value) <> "PPE" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkPS = True Then
        For Each cell In Range("BJ4:BJxyz")
            If UCase(cell.Value) <> "PS" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkSTF = True Then
        For Each cell In Range("BK4:BKxyz")
            If UCase(cell.Value) <> "STF" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
        
    If chkErgonomics = True Then
        For Each cell In Range("BL4:BLxyz")
            If UCase(cell.Value) <> "Ergonomics" Then
            cell.EntireRow.Hidden = True
            End If
        Next

    End If
    
    Loop
    
    Unload frmSort

End Sub