Here's what I came up with
Sub FORIFIF()
Dim CheckRow As Long
Dim OutRow As Long
Dim Ausgabe As Object
Dim Inventar As Object
Dim Prüfliste As Object
Dim InventCallSigns As Range
Dim Found As Range

Set Prüfliste = Sheets("Prüfliste")
Set Inventar = Sheets("Inventar")
Set Ausgabe = Sheets("Ausgabe")
Set InventCallSigns = Inventar.Range("C:D")
OutRow = 1
        
Application.ScreenUpdating = False

  For CheckRow = Prüfliste.Range("A" & Rows.Count).End(3)(1).Row To 2 Step -1
    Ausgabe.Cells(OutRow, 1).Value = Prüfliste.Cells(CheckRow, 1).Value
    Ausgabe.Cells(OutRow, 2).Value = Format(Now, "DD.MM.YYYY HH:MM")
    Ausgabe.Cells(OutRow, 3).Value = "bydo@vba.ms"
    Ausgabe.Cells(OutRow, 4).Value = "bydo"

    OutRow = OutRow + 1

    Set Found = InventCallSigns.Find(Prüfliste.Cells(CheckRow, 2))
      If Found Is Nothing Then
        Ausgabe.Cells(OutRow, 5).Value = "nicht gefunden"
        Ausgabe.Cells(OutRow, 6).Value = "nicht gefunden"
        Ausgabe.Cells(OutRow, 7).Value = "nicht gefunden"
      Else
        With Inventar.Rows(Found.Row)
          If .Cells(6) <> "aktiv" And .Cells(6) <> "wartend" Then
            Ausgabe.Cells(OutRow, 5).Value = .Cells(2).Value
            Ausgabe.Cells(OutRow, 6).Value = .Cells(5).Value
            Ausgabe.Cells(OutRow, 7).Value = .Cells(6).Value
          End If
        End With
      End If
    Next CheckRow
  Application.ScreenUpdating = True
End Sub