We have Google Analytics-4 360 licence. There are challenges in the GA4 Explore UI while looking at the exhaustive numbers and hence trying to create Dashboard using the raw data in the Google Big Query and visualize in a BI tool(Looker).

However, the Queries written on top of the raw data are giving numbers which have discrepancy of around 20% or more when matched with GA4 Explore UI data. Specially Session Source/Medium logic is something that we are unable to replicate.

Does anyone have any guidelines or way forward on this? We are really having a tough time achieving this.