What even is this post? Ughhh...I don't know why I come to this website anymore.
Anyway...
1) There aren't 'branches' of Orthodox Christianity. You're either Orthodox or you aren't.
2) The Mar Thomites in India are not Orthodox. If you are referring to
these people, they are a self-styled "Reformed Eastern Church" -- i.e., Protestants in Syrian garb. There is no "Mar Thoma Orthodox Church" (Orthodox Indians wouldn't style themselves that way, due to the association of "Mar Thoma"
as a confessional label with Protestantism), unless you are talking about a literal parish that is Orthodox that happens to be dedicated to St. Thomas, of which there are many. ("Mar Thoma" being the Syriac for St. Thomas, the founder of Christianity in India.)
3) There are no Coptic Orthodox in India, unless they're visitors/foreign workers. There are the Syriac Orthodox Indians, the Malankara Orthodox Syrian Indians, and a very small number of Armenian Apostolic from the times of a much larger Armenian presence in India (there are only about 600 in the whole country today, if that, but the presence of over half a dozen churches still existing today, a college, a sports club, a scouting association, etc. all established by the Armenian community suggests a community of probably at least a few thousand at one point during healthier days in the 18th and 19th centuries).
It'd
super cool if some day the people who are neither Eastern Orthodox nor Oriental Orthodox could stop attempting to use the Chalcedonian schism as a cudgel with which to attempt (and fail) to beat their opponents. If you can't get the basic details right about who's who and why because you don't know what you're talking about, you should probably pick a different example.
Also, y'know...the Chalcedonians split from each other much later on, and then
even later into
thousands of churches thanks to the Protestant reformation leading to all kinds of ecclesiastical wackiness infecting the formerly Latin-speaking western Christian world in particular from the 1500s until today, yet
for some reason that much nearer (geographically, culturally, historically) split is never used by these people as evidence that such-and-such's claims can't be taken seriously. Hmmm...I wonder why.
(I'm just kidding. I don't wonder why.)