I disagree. Google Takeout is a sham. It doesn't have all the data they collect about you. It's almost adequate for data portability, but not quite. It's useless for data transparency.

Google Docs keeps keystroke-level logs of everything you type, for example. That's not in Takeout. Neither are things needed to conduct a security audit (that's a paid service for Workspace customers). Neither is a lot of advertising profiling data.