I’ve heard a recent update turned the JavaScript Enabled to true at config level
It has been that way… probably forever. Quite some time ago, probably a one or two years, there was a bug with NoScript (which is how Tor Browser actually deals with JS) that meant it was necessary to use the javascript.enabled option to disable JS, and so an update was sent out with safest using that. Once NoScript was fixed Tor Browser went back to how it used to work.
but still showing as disabled to safety checks meaning JavaScript could be used against people who have it ‘disabled’ through Safest mode
No. Not unless there is a bug in NoScript.