There are many different variations between the different Protestant creeds. These differences are often nuance on beliefs rather than a schism making difference which would encourage them to be saber-rattling at each other’s door.
For example, all the Protestant religions agree on the nature of Christ. He is fully human and fully God. None of the religions differ on and in fact, this is one of the points where Catholicism is in line with the other Christian religions.
Another point of similarity is the Resurrection. All of the denominations believe Christ rose and this it is historically verified. But from here things diverge.
The basis of belief
At the root of the differences between them is where their beliefs come from. In theory, this starts in the same place, the things that Christ said during the time that he was here on earth.
That’s where similarities end. The problem with the bible is that it was not written at the time Christ was actually here, but years afterward. This opens to interpretation the actual words in the bible. Some denominations like the Anglicans and Episcopalians believe the moral authority for belief comes from both the scriptures and the church fathers.
Others such as Baptists and Lutherans base their beliefs on the Bible, and that is all. This doesn’t cut out the possibility of interpretation, is the bible the Greek one or the Latin, but it is a narrower interpretation.
The position of Mary the mother of Christ requires Christians to consider two doctrines. The first is Original Sin and the second is how Christ was conceived. The tenet of the Catholic Church is that Mary was born without original sin – she is the only one and that’s one of the things that establishes her status in the church.
The Assembly of God and the Baptist are intensely practical on this. Mary was human, born in sin like everyone else. Anglicans and Episcopalians are also leaning towards this perspective. A blanket statement is hard for them in either direction.
Where the religions align is on the virgin birth. Christ was conceived of the Holy Spirit and Mary was virginal when she conceived and when she gave birth.
Satan, demons and angels
Mary’s position and the basis of beliefs are large areas of difference and make a difference to how those outside the religion there are other theological differences. What are angels and are demons fallen angels? It does rather beg the question why if you had arrived at angel status, you would fall. It seems counterintuitive to me.
But what about Catholicism
A Pew Research survey in 2017 found that in the US at least, 57% of the countries Protestants are more like Catholics than unlike. It is an amazing position when you consider the history and the reasons behind the division.
For those who do know their history, the other 43% one assumes, this has to be frustrating and a concerning development.