At Formosa only cebu can survive. The wheather ia super hot. Entre Rios, Santa Fe, BA and Cordoba are better and a lot more expensive, for cattle.
It is 1100 from BA and it is the far west not only because it is far, wild, undeveloped, jungly.
You should be carefull about how close it is from the Pilcomayo river. It might be a fraude.
There is a bann for buying land close to the frontier for foreigners, i’m not sure if this is still valid.
Also, the Pilcomayo river change its course every year. So, the land you buy might be at Paraguay the next year.