I travel to Brazil about once a month. Brazil is a 100% credit card/debit card economy. You can use your card almost every place - restaurants, cheap restaurants, fast food,hole-in-the-wall kiosks, cheap cafe shops, taxis etc. I have even used cards in small villages in the amazon.
Having said that, there are ATM machines every where , which discharge up to 2000 reals in one shot...almost 500 usd. Of course the machine will charge you something, as will the bank.
I have not come across many cuevas in Brazil. Whenever I want Reals, I take it out from ATM. I have never been inside a bank in Brazil ( other than the ATM area).
Once you arrive at the airport, you can use the ATM machine there.
Or you can take a pre-paid taxi - using yr debit or credit card - ( all Brazil airports have pre-paid taxi) and go to your hotel and look for a machine nearby. I did not find any difference in machines at the airports or elsewhere. Personally, I avoid using at airports - as there are 100's of stories of debit cards being duplicated in Brazil after being used at a ATM in Brazil. So I prefer to use a ATM machine at some high-end hotel where I envisage, higher security preventing tampering of machine.