Fixed the issue with texture mapping when changing graphics settings (and updated the build here). Also, partly fixed the issue with Vsync: for some reason it increases render latency at the game start, but unchecking it and then checking back in makes render latency normal.
At the moment, canyon sphere is incomplete from gameplay stem point (unlike other 8 spheres), it is just empty location, so the path into the cave definitely not final. As for canyon sphere related lags, unfortunately I wasn't able to replicate it yet. I'll look into this further. Am I understanding it correctly, that lags didn't appear if you didn't go inside canyon sphere at all? As this sphere empty at the moment, I will probably just exclude it from build for some time.
As for controls (especially scale changing mechanic) — it hugely depends on FPS and even more on render latency. If you don't have screen tearing, it is better to turn off Vsync as it drastically increases render latency, and bigger latency even with the same FPS could make controls less responsive and noticeably harder. So this could be the reason for troubles with scaling timing during jump. Ideally, controls should work well in any case with any settings, and I will certainly strive for this.