When you play this game with more than 2 players, there is a strong luck element that you can't control. What I mean by this is if you are playing a 3p game with 4 options on the board and the other 2 players pick different options, you could be screwed into picking a worse card or no card at all. On the flipside, they couldve both picked the worst card and you can have the best one for free. Some can say that is the variance of the game and that this is "funner". With that I would have to agree, but that is NOT why arena mode is in BGA. If you are playing arena mode for fun and not to be competitive, you shouldn't be playing arena.
Games like sushi go have arena settings that aren't 2p as well. In sushi go someone could make a mistake that directly harms you and helps the third player (and you can't do anything about it). In 2p, you are 1v1 and everything your opponent does wrong will only harm themselves. (except in a couple rare cases)
Point is, playing most games on BGA have the most strategy/competitive based experience with 2 player. Higher player counts can be more fun, but that doesn't belong in arena.
Thank you.