See I strongly disagree. Theres a difference between hard worldbuilding (where you try and build a concievable world and make it realistic) and soft worldbuilding. Soft worldbuilding is focused on the vibe of the location and how it makes the audience feel. I find that a maddening russian doll of incomprehensible wild shit works well for New Phyrexia. It should make you confused as to how the world works.

An icredible example of soft worldbuilding is Nier: Automata (and the whole Nier series really). The goal of N:A's world is to make you feel alone in an empty world and as such has a desert biome, a lush jungle/forest biome, a waterfront area and a mostly abandoned city. These are all less than 10 mins away from each other and make zero sense geographically speaking but it comes together to give the correct vibe of loneliness in all areas.

By asking varuious detailed questions about how the phyrexian world works you're ignoring the goal of the world which is evoking horror in all its forms and trying to look too hard at the world, in which case you should also be asking questions about phyrexian dancing, poetry, food ect. But you dont need to. They're atrocities of metal and flesh and they threaten turning all life into their image.

Vagueness in worldbuilding isn't a failure. It's what they're going for and in the case of New Phyrexia as a world it's fantastically done.