Official AION 2 Global PC system requirements from Steam: minimum GTX 1050 Ti, recommended RTX 2070, 100 GB available storage and SSD guidance.
Steam says 100 GB available space . The current Steam Playtest depot is about 80.42 GiB to transfer / 81.74 GiB installed, but that is a test-build snapshot rather than a final retail-client promise. See the download-size tracker →
Steam explicitly recommends an SSD for both tiers. For an MMO with large zones and crowded encounters, treating the SSD note as practical rather than optional is sensible even though it is not listed as a hard requirement.
Official Steam AION 2 store page