Some of this information is contrary to what I have always heard and observed.... that the particular BANK that issued one a card is the entity that sets the Exchange Rate. For example you said: "USAA gives the best Exchange" and "Capital One Gives the best Exchange rate but a $2.50 fee."
My information says that it is not the actual bank where one got the card but the 'card issuer' that determines the Exchange Rate. If using a Visa® debit card from whatever bank gave out the card, it is Visa® that sets the rate, not the bank. Similarly if it is a MasterCard® card, they set the rate. AND that rate is set once daily, not 'hour by hour'. Now definitely a particular bank... that issued the card.... may have different policies about reimbursement for any fees charged by the originating ATM bank OR even add fees like your $2.50 fee from Capital One for using their card at an ATM.
Consider this: The exchange rate for international purchases and foreign ATM transactions is set by Visa® or MasterCard®, depending on your card's logo. This exchange rate is either the wholesale market rate or a government-mandated rate set every day—except weekends, Memorial Day, Christmas Day and New Year's Day—Visa and Mastercard calculate the rate for the next day's transactions.