Long story made short: apparently, the previous administration didn’t really try (since it was Bolsonaro’s, I am not surprised). EU import controls and financial interventions have also helped:

He believes the slowdown is due to a combination of factors: the resumption of embargoes and other protection activities by the government, improved technical analysis that reveal where problems are occurring more quickly and in more detail, greater involvement by banks to deny credit to landowners involved in clearing trees, and also wariness among farmers generated by the European Union’s new laws on deforestation-free trade. It may be no coincidence that deforestation has not fallen as impressively in the cerrado savanna, which is not yet covered by the EU’s controls.