Lol, no

All of them are enabled by default.

Mesh shader support was enabled by default with Mesa 23.0

GPL was enabled by default with Mesa 23.1

RT was enabled by default with Mesa 23.2

In fact, looking at Mesa env vars also reveals that.

https://docs.mesa3d.org/envvars.html#radv-driver-environment-variables

Env vars remained for those features are nogpl,nomeshshader,nort because they are all enabled by default so disabling needs env vars.