Hey! How can we combine metrics in GrowthBook from different data sources in the best possible way? We have one data source for our streaming Snowplow events and then one data source for our data warehouse. The same identifiers are present.

Hello. GB only supports 1 data source per experiment (or per metric). You might consider writing an ETL to get your streaming data (raw or aggregated) into your main data warehouse. Or implement a new data source that sits on top of both.