The first five stanzas of Dayenu concern leaving slavery in Egypt.
They present the opening stages of the Exodus story as a sequence of gifts. The song begins with God bringing the Israelites out of Egypt, then describes judgments against the Egyptians, destruction of their idols, the death of the Egyptian firstborn, and the Israelites receiving Egyptian wealth.
The fifth stanza ends this opening section by mentioning the splitting of the sea. The following stanzas move from liberation into the miracles of the journey, including crossing the sea on dry land and the defeat of the Egyptian pursuers. Thus, the first five are not a general account of the entire Passover story; they form a distinct opening unit focused on release from Egyptian bondage.
Canaan can be confusing because later stanzas mention entry into the Land of Israel, but that belongs near the end of the song. Persia and Babylon are not the countries associated with the Exodus narrative in Dayenu.