I wrapped up my trip to Portugal and successfully dodged DCC for the duration. When checking out of the Hyatt Regency, I was given the choice of €1410.00 or $1619.54 on Tuesday, which was a 3.6% DCC markup. The terminal was a Yomani XR pinpad that was customer facing with the local currency option on the left and home currency option on the right. Surprisingly, the posted transaction was using an exchange rate from August 15th, which was lower than the exchange rate on the transaction day for a total of $1,557.77, saving $61.77 by opting out of DCC.

Thanks again to those who informed me of the double decline process in Portugal such that I wasn't quick to hand back the terminal to the merchant in case of DCC.