Choosing right database for storing bank transactions

Question

I am starting a new project within GCP and I am trying to choose a right tool for storing bank transactions:

1. I don't need transactions, these will be basically write-only, no updates
2. I don't need joins and relations
3. I need grouping and sums
4. Ideally I would like to use a managed tool within GCP
5. I need to be able to have unique records (identified by ID or by the uniqueness of the record)

GCP solutions:

1. Firestore
   • I really like the way of authorisation via service accounts, no need for users/passwords
   • Fulfils 1, 2, 4, 5
   • Completely unsuitable to fulfil point 3
2. CloudSQL
   • fulfils 3 and 5, but I find it too complex for my need
   • old-way authorisation of MySQL - one cannot use GCP authorisation
3. Elasticsearch
   • fulfils 3 and 5 but also too complex
   • Not within GCP, not managed, cannot use GCP auth
4. BigQuery
   • Seems to fulfil all 1, 2, 3, 4
   • Unfortunately it seems it cannot prevent having duplicate records
   • Data becomes available after long time
5. BigTable
   • Seems too complex for such simple requirements

Could you think of another approach?