Stadia came out already at the same time, in fact you can play right away now (for those who may not know). Mac version didn't drop until the day before Early Access (5th of October) and I don't recall any mention of it being supported one way or another (other than people making unverifiable stuff up), so unless Larian specifically say something then the possibility is there. I do kind of wonder if how well or not it runs under Wine well have any impact too, I guess that's something we shall find out relatively soon.