How would you design end game monthly challenges?

The devs said that they were pretty happy with monthly challenges as a whole, which is disappointing to me.

There were released about 1.5 years ago, well before constellations were released, and Asol was the hardest content. I remember having to carefully follow the Petib monthly challenge spreadsheets to see which champions I owned, and getting 70 wins was quite difficult. Now they are so brain dead easy, they feel like chores.

To fix this, I want a second set of challenges. They are all randomly generated with certain parameters, so dev time is minimal.

They could mix and match with champion specific powers like Ezreals spell cost 1, deadly, and legendary powers like hugify or broken blade. As a monthly challenge part 2, they could have weaker rewards like essence, stardust, or gold/silver vaults, so it would mainly be a place to use your 6* champions