Looks like I lost MESA_GL_VERSION_OVERRIDE=4.5COMPAT somewhere along the line
which is why I couldn't see anything. That, plus
force_glsl_extensions_warn=true and your two patches does indeed work.

The starfield renders now but it's still missing the coloured cloud nebulae
(this -
https://cdn.cnn.com/cnnnext/dam/assets/150617071718-game-faces-no-mans-sky-ns-natpkg-00014710-large-169.jpg).

So it seems your patches (and the overrides) get us most of the way there.