As you don't have an EUM license hence this 401 error you see. You need to have EUM license to use browser_records and synth data.
Now regarding your original query we can not select data to be shown from multiple tables unless they are from the same schema. Iff two tables that you are trying to see are in the same schema can you structure a query to fetch data combining both, but not in any other case.
Hope that clarifies. Do let me know in case you have further queries.
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