MSQ

[Iscah]

The story of G'raha Tia was related to the main story, but the MSQ of shadowbringers can almost entirely stand on its own feet without any real understanding of the relation of the Exarch to the crystal tower on the source. The post-Shadowbringers MSQ is a slightly different matter, but even that could be explained away with a few lines of expositional dialogue, instead of wasting hours of each player's time going through the crystal tower raids.

We are sailing deep into spoiler territory here, but...

The thing is, Shadowbringers 5.0 was written to make sense whether you had done the Crystal Tower raids or not, because the time travel element means that the Exarch has been through those events with you even if you haven't yet done it yourself. (The non-CT version of the story doesn't quite line up, but it worked enough to make sense.)

5.3 doesn't work like that. You, here and now, are getting G'raha out of the tower, so he needs to be in there first. And for him to be in there, you need to do CT.

As I said earlier – the writers seem happy for things to be a little bit off if you haven't done certain side stories, but they won't pretend you've done something that you didn't. You need to have personally been there with G'raha, or the story doesn't make sense.