For comparison, another reference GCP customer is SnapChat who signed a 5 Year $2 Billion dollar contract with Google Cloud, as they disclosed in their IPO Prospectus. At that time (2017) they were by far the largest single customer on the Google Cloud Platform by spend. They spend the majority of that on App Engine, Cloud Storage, BigQuery, and bandwidth.

Even after this disclosure of the TikTok $800M Agreement - SnapChat is still a much larger customer in spend per year.

https://www.vox.com/2017/3/1/14661126/snap-snapchat-ipo-spen...