You can also create the P2P group yourself, it's not hard ;)

There are a number of BTC/BRL exchanges in Brazil, if that's what you are asking. There are a number of KYC-Free methods as well, including P2P trading platforms such as HodlHodl, LocalCoinSwap, LocalCryptos, RoboSats, and Bisq. But if your payment method is bank transfer or something like that, you still have a link that the seller has then between your bank and your coins.

As far as getting a 10% markup over spot via coinjoin/mixing/lightning, I'm not sure how that's done. You can try to reduce the price you pay for the bitcoin you acquire by offering a price that is competitive but yet below spot. But just spot-checking on one of the P2P platforms, .... LocalCryptos, it appears a seller will find numbers buyers ready and waiting to pay above spot:

There may be opportunities though. For instance, on RoboSats, I don't see any other buyers (which is not unexpected -- RoboSats is new, and requires Tor browser, so its userbase is fairly small yet). No buyers means you can put in an offer to buy below spot, and a seller wanting a trade promptly may come along and sell to you at your price.

Hmmm, haven't heard a lot about Brazils Bitcoin scene yet, so Idk. Maybe go to a Bitcoin meetup and listen if people already have KYC-free infrastructure