I tried to make own graphics project on vanilla MC and Fabric, but understand that for me needs rebase on Iris, and probably, Sodium. In general, I would to use transform feedback for load vertex data form GL, copy uniform data into buffer (collect draw calls), then use Vulkan API additional draw and AS building stages (I already have libs for such purpose). Also, I would Immersive Portal Mod compatibility, and fabolous graphics settings support. And I don't know how to implement into Iris draw calls...

Iris is not planned to be compatible with any Vulkan mod. Iris heavily relies on internal details of OpenGL that cannot be easily replicated on Vulkan.