We know that Patch 1.54 existed for a few minutes (relatively speaking), that isn't the issue. It was, however, never a supported patch level and again there are no mods for it. The same thing happened when ITF was released. The discs shipped with 1.62 but the official patch level at the time the EP went to market was 1.63.

What I don't understand is how this installation is being done because again that version of the macOS does not recognize the official discs. Having an external optical disc drive rather than an internal one doesn't change that.

But anyway, with official EA produced discs then codes are provided to register the game on either the TS3 website or on Origin for Mac. So the way to proceed (usually) is with an Origin for Mac install and then Super Patch. Steam has nothing to do with it; Steam does not carry TS3 for Mac, only TS3 for Windows and you don't get Steam codes with retail disc purchases as they have to be purchased separately, directly from Steam.