Since Christianity cannot agree on what constitutes orthodoxy on salvation theology, I have my own litmus test for the claims to orthodoxy of any "Christian" church.
All of Christianity for its entire history has condemned abortion, homosexuality, divorce and remarriage, and contraception.
If a "Christian" group blows it on any of these foundational moral theology principles, it has no claim whatsoever to being true Christianity. Period, end of discussion. Nix that one from any list of those claiming to represent the Church of Christ.
Once you apply that litmus test, its not hard to discern which Churches are legitimate options for claims to "biblical Christianity." Its not too hard to sort out the rest.
The Great Apostasy really began with apostasy on moral theology; most of our differences in interpretation of salvific theology are mere matters of semantics introduced by our limited ability as finite humans to understand the mysteries of the Blessed Trinity and the economy of salvation
Don't forget that bowing to idols thingy.