A good part of GCP is part of Core google infrastructure.
Spanner is used ubiquitously inside of Google, supporting services such as; Ads, Gmail and Photos. ... Spanner on the other hand processes 3 billion queries per second at peak, which is more than 20x higher [than DynamoDB], and has more than 12 exabytes of data under management.
https://cloud.google.com/blog/products/databases/announcing-...
Monarch: Google's Planet-Scale In-Memory Time Series Database, provides metrics for Google's own services and GCP Operation suite.
https://research.google/pubs/pub50652/
Zanzibar: Google’s Consistent, Global Authorization System - underpins access control across Google's product and GCP IAM.
https://research.google/pubs/pub48190/
AWS is basically the same infra Amazon runs their own business on, opened up for the world to use.
Azure is the backbone that Microsoft sells you all their cloudified Office/Outlook/etc suite of tools.
GCP is neither of those things to Google.