From Giant Envelopes to Rapidly Contracting Cores in Rotating Population III Stars from $500$ to $1000 \, M_\odot$

Population III (Pop III) stars link the chemical enrichment of the early Universe to the formation of the first massive black holes, yet their evolution remains poorly understood at extreme masses. Using GENEC, we evolve rotating zero metallicity models from $500$ to $1000\,M_\odot$ at $v/v_{\rm cri