Sorry @KristiLogos , I didn't notice that you're using lakehouse federation. In my case the extraction part was done in ADF, so I was able to use bigquery TO_JSON_STRING function to resolve this issue.
You can also take a look at below discussion and try to use autoflatten_optimised function. 
Or take similar approach as @AnaMocanu in that thread.

Solved: Best way to parse Google Analytics data in Databri... - Databricks Community - 66976