What reasoning lead you to treat this apporach as an anxiety booster? Do you refer to using productivity apps in general?
Personally it was the opposite to me - various games increased my clarity, focus and the feeling of empowerment.
Though I have to say that gamifying life is about "creating a game" - game can be too difficult (lead to anxiety) or too easy (lead to boredoom) or the right one. Just like "normal" game for entertainment.
I created subreddit to gather people that gamify their life using "gamist approach" - approach where you are playing a game with your life by having a complex game/system (in spreadsheet, Notion, apps like Habitica etc.) and it gamifies your whole life rather than small part of it.
This approach is a niche of a niche and we want to create a small community to slowly spread this idea. If you did something like that - please join and post how you gamified your life.
Subscription seems to me won't work well because the churn rate of such app will be quite high (folks will play few weeks and learn basic "quests").
Using data is very controversial as can be seen in comments - also not sure how to monetize it well.