The liberation of Exodus was not the end of God’s saving hand. Clearly, believers struggled despite signs, wonders, and freedom. Exodus 14 didn’t erase Genesis 3.
63. Christ came to accomplish a new “exodus”, to restore freedom to the oppressed. He performed many healings on the Sabbath (cf. Mt 12:9-14 and parallels), certainly not to violate the Lord’s Day, but to reveal its full meaning: “The Sabbath was made for (people), not (people) for the Sabbath” (Mk 2:27). Opposing the excessively legalistic interpretation of some of his contemporaries, and developing the true meaning of the biblical Sabbath, Jesus, as “Lord of the Sabbath” (Mk 2:28), restores to the Sabbath observance its liberating character, carefully safeguarding the rights of God and the rights of man. This is why Christians, called as they are to proclaim the liberation won by the blood of Christ, felt that they had the authority to transfer the meaning of the Sabbath to the day of the Resurrection. The Passover of Christ has in fact liberated (people) from a slavery more radical than any weighing upon an oppressed people — the slavery of sin, which alienates (people) from God, and alienates a person from (their) self and from others, constantly sowing within history the seeds of evil and violence.
Sunday celebrates the resurrection and also offers the promise of final deliverance from sin and death. The Vatican site has Dies Domini in its entirety.