For a loan calculator my client would like to display the loan amounts with 0 decimals, and the payment per day/week/month with the standard 2 decimals.
I cannot find how this can be achieved within the same form. I.e. it seems to me that the currency filter cannot be customised to only target certain fields within a form?
The currency properties for Gravity Forms is a global setting that applies to all forms and fields using currency format. Therefore as you found already the gform_currencies filter has the same scope. Using different currency settings per field is not supported.
I’m not aware of any third-party solution for it either, sorry.