Some update:
After tinkering a bit. It seems that you don't need bumblebee at all!??? I'm not really sure because glxinfo returns "Intel" as its renderer. I.e., it returns the following:
root@4f82889627cf:/# glxinfo |grep -i renderer
GLX_MESA_multithread_makecurrent, GLX_MESA_query_renderer,
GLX_INTEL_swap_event, GLX_MESA_copy_sub_buffer, GLX_MESA_query_renderer,
Extended renderer info (GLX_MESA_query_renderer):
OpenGL renderer string: Mesa DRI Intel(R) UHD Graphics 630 (Coffeelake 3x8 GT2) x86/MMX/SSE2
This is a bit confusing because the command nvidia-container-cli info r