All of the protestant denominations are offshoots of the Catholic Church. Regardless of whether they claim to represent the true interpretation of the Bible, they do not have a historical link to the early church other than through the Catholic Church. During the early centuries, they did not exist side-by-side with the Catholic Church; the Gnostics were not proto-protestants.
I do believe what you said came from a sincere heart. I’ll likewise try to give a sincere answer.
Standing between us and the original church of the New Testament, is the ecclesiastical institution that ruled for a thousand years during the middle ages, the RCC.
The $64,000 question is: is it what it claims to be, the historical continuation back to the original church of the New Testament?
A simple reading of what we see in the New Testament over against an “ecclesiastical institution that ruled for a thousand years during the middle ages” simply does not compute.
Once the Bible became available to the common man, the jig was up for the Papacy. The trappings of Romanism, the Mariolatry, other forms of paganism, and so on, is simply not in the Bible. The whole of Protestantism, therefore, has been a major “back to the Bible” effort.
Romanists point out the various denominations within Protestants, they never stop to consider that if it weren’t for the gigantic obstruction standing between us and the original church, there wouldn’t be all these. If the RCC was what they claim, there wouldn’t be all these, neither would we have all these combative threads on FR.
The RCC is the problem, not Protestants.
It is all about faith, my friend. Christianity is all about believing “the right stuff.” You are not a Christian if you don’t. And the only way we know what is the right “stuff” is to compare what we believe with the Bible. The infallible word of God vs a church that claims to be infallible.
So, are the Protestant denominations but offshoots of the Catholic Church, as you claim? No, they are a major historic effort to wrench ourselves past the spiritual darkness of the middle ages to the true faith and beliefs of original Christianity. The true “catholic” (meaning universal) faith.