Thank you Leolaia for explaining my point much better.
I would add two further brief remarks in response to a Christian:
One popular misunderstanding about textual history is that there is a clear line between redaction and transmission, hence (in the reverse order of knowledge) between textual and literary criticism. That at some point an "author" "publishes" the final version of a "book" (henceforth termed "the original") and then nothing happens except copy and translation (including possible "mistakes" or deliberate "tampering" with "the original," which textual criticism is supposed to sort out through comparative study). Actually redaction and transmission almost always overlap, sometimes for generations or centuries, along different lines (including translation and back-translation at times), before the text somehow "freezes" -- in different states. Only when one particular "edition" has so "frozen" do the scribes stop acting as redactors or re-writers and become "mere copyists". But that means "the original" is a myth. The extant editions/versions may have one common textual ancestor but it is nothing like any of them. For instance, it is practically impossible to go back from the wildly different LXX-type and MT-type versions of Jeremiah to a common Hebrew ancestor text (I mean the "book," not particular verses) and should we discover it someday you would probably find much of your Jeremiah missing. The same would likely be true of the common Greek ancestor of the Western and Alexandrine versions of Acts.
About the Masoretic textual tradition in the middle-ages, one must not forget that it is tributary to the Pharisaic-Rabbinical standardisation of the Hebrew text which occurred in the wake of the Jewish War(s) in the late 1st and 2nd centuries AD. At that point one text type (anachronically called the "proto-Masoretic" one) was selected and finally "frozen", while the others were forcefully rejected and, as much as possible, destroyed (which was fortunately not the case of the Dead Sea Scrolls, the Samaritan Pentateuch, and... the LXX which was essentially preserved by Christians). So, leaving aside the elusive issue of "truth" and "originals," there is some historical irony in Jerome's shift to hebraica veritas and the modern Western Christian insistence on the MT as the best textual basis.