Will write proper replies later, but just now it occurred to me that G'raha's expectations for the outcome of his time travel activities are consistent with a "late split" that happens during the events of 5.0, not back in 3.X/4.X when he time-traveled to the past.

He thinks he will be erased from existence once we have successfully avoided the bad timeline.

Therefore current events would still be part of the path that could lead to the bad timeline.

Arriving on the First was not the point at which the bad future was prevented.