the another msg was a response to your post: Challenges aren't represented in a fair way, as there are so many cards in this game you can't expect everyone to level all cards up to friendly levels. As in game coins are hard to come by everyone prioritises certain cards over others, meaning by default some cards will remain weak and forgotten about all together. If I focus my 2000 coins, into an adventure and mystic deck, that means my fantasy cards will fall behind in terms of level ups. Now if a fantasy card event comes along, straight away I'm at a major disadvantage. With challenge mode I find it more of a game if luck...you need to be lucky that the cards they pick to use for the event, are cards you have leveled up above friendly level.
. ... ———— Just wanna help you out here I started playing this game like 3 months ago And I too focused on upgrading my main deck I ignored Challenge games because it was hard to win But then a month ago I started looking into the rewards (there are so many materials and like 4000 coins!!) and so I changed my strategy: I started saving materials and upgrading cards to friendly levels according to what the challenge is. I spent 50 cash a few times every week, so I get like 10k+ coins and lots of materials every week, And I save them for the next challenge, I leveled up my cards so much so much faster this way, you should do the same! Now I already have a fair amount of good common cards at level 4 and challenge is a game of skill which is fun. Hope it helps