Atlassian is burning the candle at both ends; they snapped up Trello for small organizations that don't need the complexity of Jira, and AgileCraft (now Jira Align) for big enterprises adopting SAFe.
There are some interesting niche players out there. Intland Software GmbH of Germany makes codeBeamer ALM, which is targeted towards safety-critical industries like automotive, aerospace, and medical devices. These industries have heavy traceability and compliance requirements that codeBeamer caters to.
The people behind Targetprocess are good people, I hope they don't get crushed by the Atlassian juggernaut.
Where are other user stories documented for the devs?
We use TargetProcess for user stories and tasks. In the stories, I place links out to Invision for the mockups / prototypes.
There are so many choices and flavors. It really depends on how you want to use it. I mean Jira on itself can be used via various ways. As ticket system for your clients or just internal development.
Based on that you have numerous options to go for. Do you just want a scrum board or a ticket system?
Just for scrum you have things like https://www.targetprocess.com/ but you could even use the project system in github itself.
IMO just search for your demands, there are alternatives.
I can answer from a meditator's perspective:
Same as sleeping will increase your physical stamina. Meditation is very relaxing if done right. The process of meditation involves focusing exclusively on the present and on reality.
When your mind glides into the past, you may wish things were better. Or you may wish things now are as good as they were back then.
When your mind wanders into (a hypothetical) future, you may wish things will be better than they are now. Or you may fear things will not stay as good as they are.
In all those cases, there's a stress associated with the thoughts. Focusing on the present and reality avoids exactly that stress.
For a deeper look into what meditation means, I recommend reading The Art of Living by William Hart when you'll reach marathon mode(*) again.
(*) For an explanation about what marathon mode is, see the Two Sides of Speed section at the beginning of the linked article