> Last time I dealt with this stuff bumblebee was still in use.
The primus-vk-nvidia stack still uses Bumblebee. It replaces the original PRIMUS component with a version that shares the image data through the Vulkan APIs, which seems to have fewer issues with incompatible OpenGL versions (even when both the app and the compositor are using OpenGL and not Vulkan). Perhaps something about Vulkan being designed from the start to support multiple vendor backends in the same process, vs. OpenGL where you generally have to load a single vendor's implementation?
This is new to me! I'll try it out one of these days. Last time I dealt with this stuff bumblebee was still in use. There was also a hack to spawn a second hardware-accelerated X server.