The central characters of the Exodus are Moses, God, Pharaoh, and Aaron. Pharaoh and Aaron can quickly be discounted as protagonists since Pharaoh is obviously an antagonist who does wrong and Aaron, while important, is subservient to Moses. God even points out that Aaron is beneath Moses in Exodus 7:1 when he calls Aaron Moses’ prophet.
So the question is whether Moses or God is the protagonist. I would argue that Moses is the protagonist of the story. It starts with an account of his life after all and Moses is the one who has to undergo challenges. God may be the main character of the whole of the Bible, but this particular section is about Moses. God also cannot be a protagonist in the usual sense because all of the events are arranged by God (like the hardening of Pharaoh’s heart and the selection of Moses). A protagonist has to be a character that has things happen to him and then responds to those things through the course of a drama, not the arranger of events.
Israel remembers the Exodus through rituals and customs derived from the events within the story. The most obvious example is the Passover ritual. In Exodus 12:1-20 very specific details are given about how the Passover must be conducted. These regulations form the basis for later enactments of the ritual to this day. In Exodus 12:24-27 Moses tells the Israelites to keep the ritual forever and to explain it to their children. Similar things are explained like the eating of unleavened bread (Exodus 12:39). And the start of the observation of the Sabbath by the Jewish people (Exodus 16:21-30, note that while the origin of the Sabbath is explained in Genesis this gives an account of when the Jewish people start following it).
All of these rituals form a remembrance of Exodus that gives the Israel a single identity. It explains why they do the things that they do and how they are unique from other people. It is because they are God’s people and they follow God’s laws because God rescued them. During the exile, for example, they would have been seen as behaving strangely when they followed their customs but this gives them justification. This mindset is reflected in Psalm 106 when they explain the history of Israel as a history of its relationship with God (emphasizing how they are God’s people) and which explains that God will help them despite their lack of faith (offering them reassurance when they face oppression).