Exchange Rate Conversion with Date Range

Try

Converted Revenue =
SUMX (
    'Finance query',
    VAR currentDate = 'Finance query'[day]
    VAR chosenCurrency = [Currency Selected]
    VAR exchRate =
        LOOKUPVALUE (
            exchange_rates_query[usd_exchange_rate],
            exchange_rates_query[name], chosenCurrency,
            exchange_rates_query[day], currentDate
        )
    RETURN
        'Finance query'[total_revenue_usd] * exchRate
)