TLDR: Bring dollars!
I knew the Argentina would present some unique problem when visiting due to the country’s financial problems. Inflation was over 200% and the peso was artificially pegged the dollar. Ahead the trip we bought $1000, a bit more than what we needed. I figured any currency leftover can be used for future trips to countries were the dollar is in demand.
On arrival we found using ATMs to be problematic in Argentina. The maximum withdrawl amount was capped at $15000 ARS and the charge to withdraw was over $8000 ARS. At the time $15000 was the equivalent of around 15 GBP. Not great.
Almost everywhere accepted contactless payment. I either used Apple Pay or Monzo card to pay for things. For everything else we used ARS, and dollars when we were short of ARS. Tipping is expected in the restaurants when service isn’t items on the bill/check/cuenta. The $1000 notes came in handy there.
In Buenos Aires there were plenty of people offering ”cambio”, but as a foreigner this didn’t feel like the safest option. The additional risk didn’t feel like it was worth the offer of a better exchange rate. Instead we used official cambios that offered us a "turista” rate that was marginally better than what the local were offered.
In hindsight I think we got things right. I’d recommend bringing dollars, and find a cambio to buy pesos when you have the opportunity.