I don't know if this is the solution, but the amount of query flexibility you would need in your case would be very very hard to achieve using native Nostr query language in a generic way. Even if you had one MongoDB with all the data I think you wouldn't be able to do the query you need. 

 App events should include OS tag. These complex queries seem to only be needed when data structure doesn't fit your use case 

 That's what I had to do but implies data duplication. The platform information (OS/architecture) is in the 1063 event where it should belong

Anyway I was bringing it up regardless of this particular case 

 That's what I am saying - the general solution is data duplication, not complex queries. We duplicate events across relays already, duplicating fields across related events makes as much sense. 

 I can partially agree, sometimes it's a good tradeoff.  Duplicating events is not at all the same as duplicating fields though 

 I agree with that too.