I never got Gwent ads before playing it, and started playing it about 2 years ago. Well for around a year now, I'm getting countless ads about it, mainly on social media. They are about new expansions, buying favorite faction pack and whatnot. Gwent team pls stop advertising it for people who already play. I know you need info to target the right people, so why not go for those who are playing the Witcher games? Surely you can put up ads to someone who just searched "Witcher 3" online a few times, or someone who wishlisted it on GOG.
In fact, I bought Witcher 3 because of Gwent, it was awesome seeing the characters from the card arts. And yeah, both Gwent's are great. (I bought the rest of the games too, save for the board one)
But sure continue to advertise it to players who already play the game, maybe you're trying to keep them playing but that doesn't help much since if someone want to stop playing, they will stop no matter what content is put out, they might come back for a few matches, but then leave again.