Actually, it's purchasable in early July.
https://store.epicgames.com/zh-CN/p/mobiusband-4a352b
It took a bit time to pass, especially the privacy policy part.
However, the sales are not better than the first time Aqours in Tokyo.[1]
So post something here, although it may not change anything.
[1]Season 1, Episode 7 and 8. Rigorously, it's the second time, or the first time of Aqours Gen 2. (Useless rigor)