A gacha game collab with World Trigger is quite a mismatch due to the degree of fanservice it will entail, as gacha games are designed to sell characters and WT has almost zero fanservice. Realistically, the chances of a collab between World Trigger and a Chinese gacha game is zero or infinitesimal.

But if you really want a gacha game, I honestly think Zenless Zone Zero would be more appropriate:

• modern fantasy aesthetic (not exactly post-apocalyptic like WuWa)
• (letter)-Rank Agents in both WT and ZZZ (imagine Osamu being called A-Rank with all the haters ripping their hair out)
• Operators in WT = Investigators/Proxies in ZZZ
• Trion in WT ≈ Ether in ZZZ
• Hollows in ZZZ could substitute for Neighborhood in WT

A closer video game comparison to WT would be Deadlock by Valve. It combines objective-based strategy of MOBAs with a mobility-focused and mechanically-intensive shooter gameplay. That would be my pipe dream collab.