It's not the hive, dear, the ships are not remotely hive like, and Savanuth's brood is in our solar system why would a hive fleet only just start moving when the traveler awakes? Its more likely the thing that caused the collapse, the darkness. As seen in early cutscenes where we are triangles overshadow the Traveler and people drowning with pyramids.

There's no reason to assume oryx and savathun have the same aesthetic, dear. They haven't rolled together in millions of years. ActiBungie doesn't even have an idea for what the "darkness" even is.

Let me give you another reason why it can't be Savathun. Savathun's handmaidens look exactly like the normal wizards. You could chalk this up to being just reused game models... but... The Hive aesthetic on Titan looks a lot different than it did in D1. Also, Grask (a Red Legion phalanx) was Taken. Oryx is dead. The Darkness has no reason to take yet. Malok must've waited a bit till he became a selfish asshole. There's already a Herald of Savathun for the Taken. My friend, those ships can't be Savathun's because Savathun is already here.