Hi @Ariel_P and welcome in the MongoDB Community
!
I think I see what you want to do and I think I can do it.
Can you please provide a few sample documents (just the relevant fields (especially the IDs)) from subscriptions and appsubscriptionssubscribers so I can try.
If you could also provide the expected output based on these few sample docs, it would be perfect.
Bonus points if I just have to db.coll.insertMany(<copy/paste>) to insert them in my cluster.
Cheers,
Maxime.