I'm going to be excited about a probable Portugal - Italy matchup. It would be the biggest one among all of the paths to qualify for the World Cup. These teams are champion teams in the first place. It is really difficult to make a certain prediction about which team would be able to advance for sure. They both have almost the same chance actually. But still, it feels like Italy have a slightly bigger chance.
Italy was playing world cup qualifiers terribly, they were unable to win most games, achieving only boring ties against considered weak teams such as Northern Ireland and Bulgaria. And even though Switzerland isn't a weak team, Italy should have been superior to them, but they were unable to do it as well, staying in second position in group C. Considering it, Portugal seems to have some advantage over them.
However, at same time, Italy has played Eurocopa 2021 brightly and that is a very strong factor at their favour. I could even believe Italy has totally focused their effort and energy in Eurocopa until now and since it's over, they can fully concentrate their skills in world cup from this phase on.