Where to Meet in Puerto Madero
Telos are the most practical option. Hourly hotels exist in Puerto Madero or within a few blocks. Two people walk in, nobody asks anything, rooms rented by the hour. Between $15 and $40 USD for two hours depending on the place. The whole thing is completely normal here.
A lot of escorts in Puerto Madero have their own apartments. That is the most comfortable setup when it is available. Check the profile or ask when you message. If the answer is yes, logistics stop being a problem entirely.
Hotels in the area mostly do not care about guests bringing companions. Chain hotels are the most discreet about it. If you are unsure about yours, have her come to the lobby and see what happens. Usually nothing does.