I think both teams will have a higher chance of winning but Chelsea will have a higher chance because they did not do well in the domestic league last season but qualified for the Champions League and played well. Besides, they won the UEFA Conference League trophy this season. Chelsea have more experience so they have a higher chance of winning.
Sorry, Chelsea leads as the favorite to win the game. Am still rooting them to beat Fluminense. They needs this new trophy of CWC, and beating Fluminense is a must. Don't forget they have agent in Fluminense, Silva. My prediction is also totally different than yours. They have like 65% of chance to win the game. So i think there will be no extra time nor penalty. It will be full time, Chelsea win 2-1.
Initially they weren't given the chance to go this far in the competition, but they have been doing just fine till this semi final encounter between them and fluminense, which I believe that they will be too strong for them, besides if you look at their odds they are the bookmarkers favourites in this game, so that alone speaks volumes that they are the favourite in this game.
Though it's going to be a tight contested affair, but I believe that Chelsea will have more in their sleeves to go to this fluminense side regardless of what most football rivals fan thinks.