It's not even effectively taxing the rich. The government simply set a goal of 0 budget deficit.
In Brazil the government spends budget is divided into primary spends and nominal spends. Primary spends are the amount the government spends on health care, education, social benefits, infrastructure, research, military etc. Nominal spends are financial expenses (treasure bonds interest rates, securities etc). So the workers' party government goal of 0 deficit is basically about reducing primary spending to a value below the tax revenue.
Whose interests this policy and budget goal favors? The financial sector. The government put a lock on primary spending, in a way those spendings can't grow in the same pace the population grows or gets old. It can't run a deficit to increase the amount it spends on infrastructure and services. Even if the government increase its tax revenue, it can't increase spending, since there's a lock limiting government spending.
So how the financial and banking sector profits from this? Many of the government state owned companies will start having budget issues, meaning they can't provide services properly to the population. Meaning, to increase investment, they need private money, meaning opening a door for privatization. Secondly, any tax revenue growth that surpasses primary spending will only be used to pay financial expenses, meaning more interests and bonds issued paid by the government to the financial sector, who will probably use this new money to buy off state assets.
So the government is basically pushing a right wing agenda with leftist rhetoric. And using a good, but meagre policy to make the left militancy to support the right wing policies that will come in the same bill.
I think Brazil is currently an anchor pulling BRICS down. While most BRICS countries seek sovereignty by getting as far from US dependency as possible, even though not necessarily harboring anti-imperialist takes, Brazil is selling even more of its industry to other global powers, even defunding is military industry (Avibras and Embraer) and depending more on US and Israeli tech.