Still in 2022 there's no good software I can find for managing game design tasks that's better than Google Docs.
The solutions out there are so featureful but so fatally clunky due to the weight of their features. Can't decide if they want to be used by creators or managers.
Sometimes I think of game design like putting each idea on trial. I am prosecutor, defense, judge and jury, each in turn.
Write it. Bolster it. Question it. Attack it. Try to replace it. Make alternatives. Recess, reconvene. Judge. Sentence. Implement, discard, or deep freeze.