UPDATED

The popular mod Create causes extreme frame skipping in random directions from their optimization engine. Turning their engine to OFF rather than INSTANCING fixes the performance drop.

Client-server analytics

As far as I tried investigating the cause, going towards the point of extreme frame skipping where it begins freezing is untraceable by spark, or I'm not reading spark correctly.

The issue occurs when looking towards a specific direction, including the blank sky.

Minecraft: 1.20.1
Oculus: 1.6.4
Rubidium: 0.6.5

Without the issue (Lower FPS, no frame skipping)

With the issue (Higher FPS, constant frame skipping)