running on NixOS: not connecting to headset

I am on NixOS 20.09, running SteamVR, a Valve Index headset, the GPU is GTX 1080 TI

Upon running

./result/bin/simula

Simula starts in a window, such that I can see Simula on my regular screen. The headset doesn't display Simula.

This is the terminal output:

Unable to init VR runtime: vrserver internal error (124)
Failed to initialize VR interface.
Missing Wayland requirements for glamor GBM backend
glamor: 'wl_eglstream_display' not supported
Missing Wayland requirements for glamor EGLStream backend
Failed to initialize glamor, falling back to sw

After trying around, I got

Unable to init VR runtime: Installation Corrupt (101)
Failed to initialize VR interface.
Missing Wayland requirements for glamor GBM backend
glamor: 'wl_eglstream_display' not supported
Missing Wayland requirements for glamor EGLStream backend
Failed to initialize glamor, falling back to sw

and finally:

Unable to init VR runtime: Another app was already launching (117)
Failed to initialize VR interface.
Missing Wayland requirements for glamor GBM backend
glamor: 'wl_eglstream_display' not supported
Missing Wayland requirements for glamor EGLStream backend
Failed to initialize glamor, falling back to sw

I tried both, SteamVR 1.16.10 and the beta version 1.17.8.

Start by running ./result/bin/simula on the reported NixOS 20.09, SteamVR, Valve Index, and GTX 1080 Ti setup, then compare the VR initialization errors across SteamVR 1.16.10 and 1.17.8. Done means Simula initializes the VR interface and displays in the headset rather than only in its desktop window.