How are you accessing the data? A human looking at the native Airtable interface on a computer? Via the Standard REST API?
Airtable is not designed for calculations across records in the same table, which is what you are requesting. Formulas fields can only perform calculations within a record. Lookups and rollups only work across linked records.
You could use Airtable’s new automations to do the calculations for option 2. However, depending on the number of users and how quickly their balances change, you might run into automation limits on the number of updates, processing time, runs, etc.