I would highly recommend visiting the missions of Bishop Rodrigo Da Silva if you have the opportunity. I knew him since he was a Benedictine monk as Bro. Miguel. The story of Bishop Rodrigo meeting Bishop Dolan by chance in an airport in Argentina or somewhere like that is how I remember he told it to me. I got to know him very well over the years. He was at my wedding, presided over by Dom Thomas de Aquinas. He has stayed at my US residence and I stayed for a short while in his seminary in the old location. I would not say he is of the extremost Sedevacantist type though he is an absolutist, he worked closely with Fr. Hector Romero who is sedeprivationist. Fr. Hector Romero assisted him in his seminary when it was still connected with the Franciscans in Brazil.
I also got to know Dom Thomas from Holy Cross monastery and stayed many time for a short while in the Holy Cross monastery. I have nothing against them and no reason to hold any grudge whatsoever. There were simply some issues like other people here pointed out. As prior of his monastery, he has no authority outside of his monastery. His flavor of Traditional Catholicism crosses over into cult-like behavior when things like men must never in their lives where blue jeans for example or they are not really Traditionalist. Denim is said to be a modernist material and would make one a modernist wearing it. God forbid you question the ordination of a Novus Ordo priest working with them. And lets point out that the priests of Bahia say the Asperges Mei and Leonine prayers at nearly every Mass to the extent that you leave not knowing if you attended a High Mass or Low Mass. Speaking of formation. And that’s not even mentioning how they ask for donations internationally for things like their school which has maybe 2 lay teachers and a dozen students if that. So the sedevacantists have definitely grown substantially in Brazil at the cost of the resistance, but it’s only the fault of the Holy Cross monastery. But just don’t ask who ordained their priests or you’ll likely be excommunicated. Especially if they see a pic online of you in your work clothes wearing denin.