The prevailing narrative after the Vance victory is that Trump still maintains his control over the GOP. The reality is more nuanced than that.
Vance won a clear plurality, but nothing like a majority, when faced with opposition you can clearly identify with the PBP and CL factions of the GOP. As a result, his victory looks a lot like Trump’s victories in the 2016 primaries, when he rarely received a majority of the votes.
The problem, of course, is that the Reactionaries are using their plurality to dominate the GOP, and the more moderate, principled groups are doing nothing to stop them. In that sense, it doesn’t matter whether Trump has the support of the entire GOP or not.