Thanks for reading and sharing your concern.

Former colleagues from Veolia now working at L'Oréal and (re)implement the same logic as this one described.

I'm also surprised not to see more people asking for this use case. Or many use 1 to 1 or 1 to many events, and never many to 1 processing. It's weird

On Azure, you should be able to do easily the same with CosmosDB. My code is pretty simply, and only 1 file perform the persistence logic.