Liberal, historic mainline Protestant denominations have all but completely abandoned Scripture.
They can hardly be considered churches any more when they don’t teach the truth found in Scripture.
As far as those examples, they are no more major than the ones that exist between the EO and RCC.
I will grant your reply about the Liberal Mainline Protestants but the question of the need for Baptism or the dispute between Arminianism and Calvinism is hardly of little import.