So the objective here is to complete ALL daily quests a day for 5 days.
One of these daily quests is “Make progress in a challenge”.
I have already completed the other weekly challenge.
So in order to make progress in the Max. Productivity challenge, I will need to complete a quest that requires making progress in it…
TLDR; this challenge is impossible unless you have another challenge open. I don’t and so will have to spend diamonds on one in order to complete the Free weekly challenge. Poor game design