account_statement_import_online_ponto - Better support for services such as WISE.com and IBAN accounts reused for multiple currencies

[whotopia]

Is your feature request related to a problem?
In my Odoo 14 environment, I have enabled account_statement_import_online_ponto and myponto services in order to obtain bank account statement details from wise.com. I am looking at this option as an alternative to the challenges reported in #728

Describe the solution you'd like
Wise.com provides the ability for a client to have buckets (kind of like accounts) but in several currencies. In some cases the underlying banking details are different, however in others the same IBAN account is reused for multiple currencies. e.g. for CHF and GBP. This poses a problem with Odoo's native behaviour for several reasons:

1. Natively Odoo stops you from creating bank accounts with the same number but different currencies (_sql_constraints in odoo/addons/base/models/res_bank.py )
2. I don't believe (could be wrong here) that the account_statement_import_online_ponto addon can distinguish between 2 accounts with the same name but differing currencies either.

Describe alternatives you've considered
I can get around the 2nd issue above by creating separate myPonto.com integrations with differing credentials, and assigning one of the IBAN currencies to each.

However, for the general problem of the multiple accounts with the same IBAN, this still becomes an issue. Within Odoo itself, I have forgone recording the 'correct' IBAN number in the bank account, and added CHF and GBP to the end. e.g.
GB29 NWBK 6016 1331 9268 19 GBP
GB29 NWBK 6016 1331 9268 19 CHF

This is very inelegant, but Odoo accepts these strings as non IBAN numbers. However, then the account_statement_import_online_ponto won't work because the sanitized account numbers, which will be derived from those strings, are wrong and won't match what the ponto API / WISE is returning.

The elegant solution here would be to add an additional field so that one could explicitly specify the ponto account (and perhaps the currency as well), instead of it being derived from what is already in the Odoo database.

Has anyone else run into this issue and figured out another way around it?