Currency exchange rates for local currency in each company and additional reporting (Consolidation) currency can be entered once to apply for all companies.
First we open up page for Currency Exch. Rates CONS.

In the opened window we enter currency exch. rates either straight into lines or use action Edit in Excel (SaaS) which would download Excel file that you log in using M365 can edit and publish changes.

To make these currency exchane rates available in all Companies you need to select Action Update to all IFRS Companies.

How it publish all currencies is it uses inverse currency exchange rates. For example BRL to EUR would become EUR to BRL in companies where BRL is local currency.