Honestly, the plot points themselves were fine it’s the execution that made it terrible. The pacing was off, character interactions and motivations made no sense, yes. But the broad-brush strokes of the plot could have been done well.

from what I gathered from interviews etc, the ending itself (e.g. where each character went or did) is basically set by george. Just the way show got there was written by the show writers

So yes, the ending is by George, the execution by the show runners