Two matches, two different shapes. In Ohio, both sides are MLS teams that create a lot and defend loosely, so the final should be open rather than a tight cup game. In Sao Paulo, the second leg of a semi-final is shaped by the aggregate: one team can sit and counter, the other has to chase.
Columbus v St. Louis: Columbus are shot-heavy and strong on set pieces, averaging about 1.7 xG for and 1.3 against across nine games with stats. St. Louis come in at about 1.8 xG for and 1.4 against over seven, and they give up around 16 shots a game. Both defences just allowed 23 and 27 shots in their last outings. Columbus are missing fullback Camacho, and St. Louis are thin in midfield with Durkin, Wallem and Pompeu out, while Navarro is cup-tied. That leaves space on both sides. A prize and a continental berth mean near-full strength is likely, so I expect chances at both ends and I'm on the goals side.
Palmeiras v Fluminense: Palmeiras won the first leg 2-1 despite only 30% of the ball, with 1.18 xG to 0.48. Over nine games with stats they average 1.9 xG for and 0.9 against, against Fluminense's 1.1 for and 1.7 against, and they kept seven clean sheets in ten. Fluminense hold the ball but make few shots, and they are without Kennedy, Alisson and the suspended Arana, with Cano uncertain. Palmeiras can defend the lead and break on the counter; one goal from that would force Fluminense to open up. That's why I'm siding with Palmeiras to win at home.