I have stayed at the Hilton Puerto Madero a number of times in the past ten years, most recently in early March 2020 (pre Covid, just before the border closed). I assume this is the Hilton property to which OP refers. The hotel website this morning indicates its restaurants are open with some service limitations but the Executive Lounge and Spa are closed. But to respond to OP's question, I book the least expensive available room and have always been upgraded, usually to an Executive Level room. It helps that I am a repeat guest and the staff remembers me. All of this being said, as stated upthread it is unlikely foreign tourists will be allowed into Argentina in the near future.
I have also stayed at Hilton's other BsAs property, the Anselmo (Curio) a number of times since it opened in 2015. It has never had an Executive Lounge or Executive Level, and has only a few suites so room upgrades are very limited.