Coop.
Coop matchmaking with 2vs2 matches. You could play with another random player on your side with a lorefriendly ally faction or even the same faction. For example Scoia'tael + Nilfgaard on your side vs Northern Realms + Skellige in the other side or Monsters + Monsters in one side vs Skellige + Monsters in the other side, etc.
2vs2 would be crazy and super fun, because your ally player would interact with your cards on the board along with your cementery (E.g. Monsters or Skellige factions)
Please think about this. You could do this easily with 5 cards from your faction deck and the other 5 cards from your ally faction deck (10 cards in one side, 5 from your deck + 5 cards from the other coop player deck in the first round, both ally players could interact with all their cards, 50 cards minimum in a cooperative deck, the 2 other player skins in the right corner of the screen, etc) 4 players in total per coop match.
Please think about this. It could be amazing.
Add also the third row from beta gwent and The Witcher 3 gwent, you can do this and it'll fit perfectly if you zoom out the camera view perspective, you know making the point of view a little further. This way everything will fit on the screen, and please don't tell me that you can't do this because mobile devices, because mobile phones nowadays have bigger screens than my PC monitor... so don't be lazy, we want the third round for more possibilities and more fun. The game can be boring sometimes without new game mechanics. Sorry but is the truth.