Hey @karstenkoehler
I tried it using the association label, we can mark the renewals by association labels.
Created a rollup property for counting the number of association labels marked as renewals and put the condition if the deal was closed or not (just one condition)
It gives you total active renewals, you can create an another property where you can subtract “Number of open deals - active renewals number” from above.
We can automate the associations labels as well I think using workflows - Next working on that
Thanks for your insights above. Just wanted to share with others