Are Roman Catholic and Greek Orthodox churches different from American Protestants?

I am a Korean believer in American Protestantism, but I think Roman Catholic and Greek Orthodox are Christian.

Protestantism was separated from Roman Catholicism in Christian history.

After the fall of Rome, Roman Catholic and Greek Orthodox went to war with Islam, contributing to European Christian civilization.

Roman Catholic and Greek Orthodox had a long war with Islam before the arrival of Protestantism.

The Italian Renaissance, which created the modernity of Europe, was also created by Roman Catholics.

Defining the Virgin Mary as the Mother of God, denying the Catholic worshiping tradition of prayer, but there is still a credit for the creation of Europe as a Christian civilization.

I'm a Korean, so I don't know about the war and confrontation between Roman Catholicism and Protestantism, but at least I know that Protestantism was separated from Catholicism.

In my opinion, if Roman Catholicism is defined as heresy, Protestantism is not orthodox.

Martin Luther, the founder of the Reformation, was initially a Catholic priest.

I don't know the theological debate, but I admit that Catholics appeared before Protestantism and created the Christian civilization in Europe.

Could Protestantism be born if there were no Roman Catholics?