Is AION 2 on mobile?
Not the global version. The AION 2 that launches worldwide on 5 October is a Windows PC game on Steam and PURPLE, and NC has not announced a phone version of it. The AION2 app you can find in the App Store and on Google Play belongs to the separate Korean and Taiwanese service.
NC answered the question directly in its pre-release FAQ:
“Will AION 2 be on mobile? The global version is currently being developed exclusively for PC platforms.”
So what is the AION2 phone app?
Apple’s App Store in Korea lists AION2 from NC Corp., the Taiwanese App Store lists AION2 from NC Taiwan, and NC’s AION2 is on Google Play. Those apps are the Korean and Taiwanese AION 2, which opened in those regions ahead of the global release and runs on phones as well as PC. NC’s Korean controller guide even has a section for telescopic controllers, the kind that clamp around a phone.
That service is not a way into the global game. The Republic of Korea and Taiwan are both on NC’s list of places where the global version can be neither played nor paid for, and NC has not announced any link between accounts or characters on the two sides. How the versions differ is covered on the Taiwan and Korea versions.

What to play it on instead
A Windows 10 or 11 PC is the only way into the global release. The floor is a GTX 1050 Ti with 4 GB, 8 GB of RAM and 100 GB of space; the full table is on system requirements, and both launchers are walked through on download and install.
If what you want is to play away from a desk, a controller gets part of the way: NC says the game is playable with one, without promising full support at launch, and Valve has not tested the Steam Deck. Both are covered on controller and Steam Deck. NC’s wording is about the present, so a phone version of the global game is not ruled out, only unannounced; the platforms page will show it if that changes.