"If you believe that ego depletion is real, you experience it." -- wow, sounds spooky, fascinating if true
"If you experience ego depletion, you believe that it is real." -- yes thank you, Captain Obvious
To me it seems like different people have different capacity for making decisions (that's kinda what ADHD is about). If you can make 10 different decisions a day, but you are required to make 20, you experience "ego depletion". If you can make 30 different decisions a day, but you are required to make 20, you laugh at the idea of "ego depletion", and you can even help to debunk it experimentally by increasing the required decisions to 25 which you can still do easily.
An analogy would be if you talked to people who have broken legs and found out that they are unable to run. So you come with a hypothesis "all people are unable to run". Then someone else tests the hypothesis using both people who have broken legs and people who are okay, and then conclude "actually, the only people unable to run are those who believe that they are unable to run", which is technically true, but misses the part where the people believing that they cannot run are the ones with broken legs.