You err in asserting that the Catholic Church is merely a later offshoot of the original Church of Christ. In truth, the Catholic Church is that original Church, founded directly by Christ upon the Apostles, with Peter as its visible head: “You are Peter, and on this rock I will build My Church” (Matthew 16:18). This Church has endured continuously, not for 450 years, but from Pentecost to the present day, safeguarded by the Holy Spirit as Christ promised: “I am with you always, even to the end of the age” (Matthew 28:20). The notion that all denominations are equal descendants of an extinct Church contradicts both history and divine revelation.
One must distinguish between legitimate development of doctrine—guided by the Holy Spirit and affirmed by the Magisterium—and the invention of man-made teachings that contradict apostolic tradition. Saint Paul exhorted the faithful to “stand firm and hold to the traditions which you were taught, whether by word of mouth or by letter” (2 Thessalonians 2:15). The Catholic Church has preserved these apostolic teachings through Sacred Scripture, Sacred Tradition, and the authoritative teaching office (Magisterium), as affirmed in Dei Verbum §10. Protestant denominations, by contrast, arose centuries later through schism and doctrinal innovation, often rejecting sacramental theology, apostolic succession, and the Eucharistic Real Presence.
To claim that Catholic theology is a corruption of Christ’s original teaching is to ignore the historical continuity of the Church, the witness of the early Fathers, and the promises of Christ Himself. The Church is “the pillar and foundation of the truth” (1 Timothy 3:15), not a human institution subject to decay or reinvention. You are called not to relativise ecclesial truth, but to recognise and submit to the one, holy, catholic, and apostolic Church, through which Christ continues to sanctify and teach His people.