Maybe, but unless we're in there, it's hard to say for sure. Battleye supports it but given the clusterfuck that is the Tiger engine, they might be using an old or heavily modified version. Especially given how easily cheaters are getting past it atm, I would not assume they're keeping up to date on it without some evidence.

Stadia limits the player's control of the system substantially and might not have even needed the anticheat, or the same anticheat, given it's closer to a console in terms of user's ability to run programs alongside the game to modify memory.