In the past year or two, I've had mostly bad experiences dealing directly with Argentines, ranging from doubling the rent in usd, taking stuff out of the place, being generally shady, etc. It hasn't always been like this, but now it is.
These days, I'd recommend staying in cabana/aparthotel type places specifically for tourists for short term rentals, in which case google maps is probably the most efficient way to find it. I've had 95% good experiences doing this, although it's more expensive, they're professional & you can often pay with your visa and get a 20% discount.
Apart from that I'd say book on Airbnb & pay the premium for the relative safety the platform offers, the truth is, these days doing cash in hand deals directly with Argentines you don't have a strong history with is quite risky, a lot can go wrong.
Also, there is another previaje coming up in May, which almost guarantees that short term housing supply is going to be limited even further.