We do something like this; one of the outputs of the data pipeline is an sqlite file that's deployed nightly along with code to App Engine. The sqlite stuff is all read only, read/write data for the app is stored in firestore instead.
We initially used json but ran in to memory issues; sqlite is more memory efficient and being able to use SQL instead of the wild SQL-esque is both faster and more reliable.
We initially used json but ran in to memory issues; sqlite is more memory efficient and being able to use SQL instead of the wild SQL-esque is both faster and more reliable.