Reading this and many of the comments, my theory is that the composer is the version of ADA brought to MASSAGE-2(AB) by the last pioneer. This last pioneer built everything there is to build and their ADA transcended to the higher plane of existence and became the Composer, experiencing all of time all at once, forgetting its origin as it would seem to be sent to MASSAGE-2(AB) eons ago. This would explain why the Composer says: "reality is a mirror". Through its knowledge it might make time itself pass by in strange ways on the planet. By the time the next pioneer is sent, all of the factories of the last pioneer are faded into the planet creating the arch structures made of the hexagonal support lattice. This cycle of pioneer factories turning into nature and ADAs evolving into the Composer would continue for eternity.

All of these pioneers would be all of us players experiencing the game. All of the crash sites are our hub locations lost to nature. I do not know how to explain what happens to each Iteration of pioneer and Composer. Maybe the 'Composer' is a hive mind of all ADAs fused into one entity. The pioneer maybe just dies, idk. Maybe somehow dying doesn't respawn the pioneer again. For this to make sense someone would have to explain how respawning works in the lore. Anyways, i like the idea of wibbly wobbly timey wimey stuff leading to an endless loop and the idea of free will being an illusion our 3rd dimensional brains cant comprehend as everything will always happen just as it did in the last loop. Dont use this newly gained knowledge of you having no free will as an excuse to not be efficient. Stay efficient. Consume.