Will using T7x get me VAC banned from the official Steam servers (or other internal Black Ops 3 servers)?
No, it will not. The game has been extensively studied by the community over the years, and the consensus is that VAC (Valve Anti-Cheat) is entirely absent from Black Ops 3. Additionally, Treyarch has not implemented any other anti-cheat measures capable of banning users from their servers.
This conclusion is supported by years of evidence. Historically, hackers have operated freely on the Steam version of Black Ops 3, even before public pressure and a gaming journalist’s inquiry prompted Treyarch to address the situation. While they fixed remote code execution (RCE) exploits, the fundamental behaviour of the game remained unchanged.
As a result, using T7x will not lead to a ban from official servers.