Christians are very much one as all are one at the genus level. For instance all mammals are so categorized for having various characteristics in common.
This does not mean that there are no differences between a shrew and a blue whale.
Honestly your warped logic never ceases to amaze.
In effect then there is only one "religion" because all those separate religions are so categorized by all their followers engaging in belief of some kind. They all engage in prayer/meditation of some kind. They all think their way is the right way.
Reality check. A wolf is not a deer. They may share some traits like having 4 legs but they are fundamentally different animals.
One will readily attack the other and devour it.
Christian divisions gave us long wars. Protestants vs Catholics in Ireland for example. Religion itself has given humanity more and bloodier wars than anything else.
In the end it's about power and control. The endless fight for supremacy and the right to exploit and control the dumb masses for one's own ends.
Humanity will not progress or evolve until it rids itself of religion in all its forms and those who wilfully exploit the weakness of others.