>Are there even any conflicts on the horizon in macaco lands?
Regular violence (50 thousand homicides per year) could already be considered a civil war, with cartels as insurgent groups. But nothing that looks like a regular war or insurgency is in the horizon. Maybe FARC or another insurgent group in the Amazon might dare to make another cross-border raid.
For the past few decades, the nightmare scenario in the Brazilian military establishment is a First World country or coalition (e.g. France) invading a resource-rich area in the Amazon on behalf of "the environment" or "oppressed Amerindians". But this won't happen under the current leftist government.
>How does jungle warfare even look like?
In counterinsurgency: meticulously collect information with undercover agents, then behave like an insurgency, dispatching small, stealthy teams of special forces to decapitate the insurgent leadership and hunt down the remaining insurgents (the Araguaia model).
In an invasion by a superior conventional military: apply the Vietnamese model (insurgency until the enemy loses the will to occupy your territory)
In a conventional war with a peer adversary: Brazilian doctrine holds that this should be solved with a quick offensive, but that sounds unlikely, even if a lot of helicopters were used.
In this theatre, civilian transport is mostly through rivers, roads are scarce and muddy. Hence the Navy should have some gunboats, but small transport aircraft will offer faster logistics from urban hubs to forward bases. Then use helicopters from those bases to the frontline. Maneuver forces will have to be light infantry, partly drawn from the local population or at least with local guides. Just as other terrains dominated by light infantry, forces will disperse into smaller groups and fight by infiltration.
For a lengthy exposition, you could read this article by a Brazilian colonel, with American commentary at the end:
>How is the military tackling the cartels ?
Outside of border security, tackling the cartels is constitutionally a police, not military attribution, unless civilian authorities call in the Armed Forces in exceptional circumstances. But exceptional circumstances happen all the time, so you get >>46710
. Garrisoning troops in the favelas was mostly a thing of the past decade, though. So nowadays the military isn't doing much.
>What do you think would be the best way to remove cartels out of these southern shitholes?
The Bukele model is highly successful, but El Salvador is tiny and even a strong dictatorship would find it difficult to scale that model to a continent-sized country.
In any case, cartel removal would require a serious and creative counterinsurgency. It's not a generic "war on drugs" but a war between the state and insurgent groups defying its sovereignty (this is also a strong case for using the military, as the defense of national sovereignty is one of its normal constitutional attributions). Consider geography, for instance. The classical Rio favelas are defined by their density and inaccessibility to motorized transport - an impenetrable human hive. Maybe some highways should be blasted into them to give the state easy access. This will remove a lot of houses, but new settlements can be built elsewhere, or on unused land and buildings in the city center. Furthermore, the classical favela is built on a steep slope with access to a wooded mountaintop, offering escape routes for the insurgents whenever the state invades the area. Maybe there should be permanent military/police garrisons atop the largest massifs.
None of this is happening, cartels administer favelas right beside upper-class neighborhoods, where the state is supposed to be at its strongest. If they've never been dealt with it's because they're part of the system and serve some purpose for the ruling classing.
A better scenario under the current system is São Paulo, which has lower crime rates and is generally far better run than Rio. Apparently the dominant cartel has a deal with the government and enforces a reduced level of violence.