sadface. Brazil is pretty laser-focused on that CV, so making components for Pedro is really hard. Maybe his numbers are just too big? I can remove some base yields and the tourism at Radio. Maybe that's enough?
That's an unfortunate problem with a few civs, yeah, and Brazil is one of the biggest possible offenders because of how it wants to snowball GAs permanently in the late game, and anything that makes this occur earlier has exponential scaling, whereas a lot of other UCs don't have that issue. It also sucks that Brazil just... doesn't really have much to focus on as a civ other than CV, nothing else makes sense.
I think there are a couple of ideas to work with to some varying degree:
1) Push Sambadromes to be a later building. Brazil didn't start construction of these buildings until very recently, with Rio's being as recent as the 80s. Even the idea of the Samba Schools and more formal Carnival parades isn't a century old, starting in the first half of the 20th century. They'd make a great replacement for Stadiums since that is literally what they are, and by pushing them back they can be allowed to be incredibly strong without the current problem of Brazil getting its perma-GA flowing in Renaissance and getting too much of a head start going into Ideologies. I'd even be fine with them getting buffed if it is too late in the game, focusing this entirely around enhancing the Carnival mechanic.
2) Nerf the yields that allow Brazil to too quickly snowball, the two big % yield modifiers, and if necessary replace them with someone less recursively snowballing. The issue with the current building is that once Brazil hits its stride with GAs, it has no unhappiness, 25% culture, and massive tourism and gold bonuses. With 25% GAPs during GAs, Brazil's permanent GA threshold has been moved forward a ton, and this can start snowballing in Renaissance in 4UC, at which point Brazil's UA turns into "this civ doesn't have an unhappiness system, has 35% increased Culture, and every GA start is like getting a Great Merchant and Great Musician bulb".
Personally I'd go with 1, it reinforces that Brazil is a late-game powerhouse and if you wait until Stadiums, you deserve to lose. And it nicely divides Brazil's UCs into Colonial Brazil and then Modern Brazil. I also don't think there are many Stadium replacements?
Also yeah, Brazil is powerful without 4UC, but at the very least we can tidy things up pending G fixing the rest of Brazil.