The idea of the daily challenge is fun because it levels the playing field in terms of RNG seed and team composition, therefore leaving the only difference to be on the player's own skill and tactics, but it feels like not many people take part to score on the daily leaderboards.

Maybe because it just lasts for a day? So what if there was also a monthly challenge?

This would allow more people to score on the same specific challenge, and it'd be fun to see the leaderboards getting filled up as more people try it.