How to update first empty object in array?

@kerbe Thank you for the additional explanation. At this point, I do not have the context of your overall application, and the setting for your application. I have too little knowledge and definitely too little data. I might be able to say more if I saw a sample collection with about 20-100 documents in it that together fully represent your data structures and help illustrate the data that you have, and how you intend to update it.

I do not fully understand your use or business case. So I do not feel I can say much more than I have.

Best wishes to you!

Thanks so much

Bob