What is your use case for doing a daily granular CUD analysis?

There is a sample query where you can potentially modify the time range to query by day. I haven't tried this since I rely on the console. I can't confirm if this works but please share your working query if you create one.

https://cloud.google.com/billing/docs/how-to/bq-examples#cud-queries

Also, as far as I know, there is currently no API to get this data.

https://stackoverflow.com/questions/77155333/api-for-getting-gcp-committed-use-discounts-and-its-applied-resources