[QtQuick3dXr] Vulkan performance much worse compared to OpenGLES on Quest 3

I saw the recent commit on the 6.9 branch: 72a4c47dce135878eb59eb7601b6884d1a59067f use vulkan on Android

I'm currently developing an XR application for machine digital-twin simulation at ASML and decided to switch the graphics API to vulkan. To my surprise Vulkan performs much much worse compared to OpenGL ES in the exact same scene. 

Vulkan: 63-90fps with 65% GPU utilization and CPU utilization on all cores below 60%

OpenGL 120fps with 85% GPU utilization and CPU utilization on the highest used core at 80%.

MultiView rendering is enabled with both API choices.

We are targeting a locked 120hz on Quest 3 and are able to do so just fine so far. We use a slightly modified version of QtQuick3D to set 120hz in the headset.  This one line in QtQuick3DXr qquick3dxrmanager_openxr.cpp and recompile:

But hearing OpenGL is deprecated for Android 15 has us a bit worried. We'd hoped Vulkan could offer better performance over OpenGL, certainly not worse.

Is this known? If required I'll make a little example app to show the difference but I suspect you'll see this difference in all examples that stress the gpu a bit.