It’s really frustrating reading this thread looking for an actual answer to the question of “how would Brazil enforce any of its demands?”
What a court in Brazil can do in case of a "no", is then block the whole website, often done in simple ways (DNS) at local ISPs. It can also put the burden on local representatives of Rumble in Brazil, as it did with Facebook in the past (this means jail time for not complying with a court order).
In theory some people below mentioned that it can also forbid local Brazilian entities from performing commerce with the entity (like eg: fining advertisers paying for ads, or the advertise), but I'm not sure how that would work, since I'm not a lawyer.