Here's my genuine and honest question: What does "owning your chronic fatigue" look like in practice?

Having the knowledge about how your own mind and body work is essential when it comes to dealing with the challenges you are presented with. Having a diagnosis of some kind doesn't let you off the hook. But it is comforting to know that it isn't your fault. You aren't a lesser person because of it - you are just going through the game of life on a different level of difficulty than you expected, and a different level of difficulty than someone without that same challenge.

It would be exactly the same thing people expect from people with mental disorders. You must manage your disorder in such a manner that to the outside world it appears as though you don't have it. Which is totally not an unreasonable ask and definitely not exhausting and untenable to have to fight against your own body for 16 hours a day.

You can't blame your disorder so no turning down plans because you don't have the energy today—better take another dose of stimulants and power through! And don't you dare ask for or expect any kind of accommodation because that's just using your diagnosis as an excuse to be lazy.