Could this have been one of the old Vex strikes?

The Pyramidion on Io is a decent match. It was a strike with other players, and its huge white Vex structure has platforming and a clean, almost otherworldly look. The route mostly winds deeper into the structure rather than steadily climbing, though, so that part may not line up.

I’d also check A Garden World. It was a Mercury strike with bright Vex spaces and sections of traversal. If the memory is more about a surreal, pale environment than one specific tower, that could be it.

The Whisper mission is another possible match for the platforming and contained feel, but it’s a weaker fit if you clearly remember other players alongside you. It wasn’t a standard activity with random teammates, and its spaces weren’t uniformly bright white. I’d compare screenshots or videos of the two Vex strikes first.