I think the language in his video is very important and different than "admitting defeat" with his beliefs. He just admits that he didn't believe the 24 hour sun in the southern hemisphere, and that specific belief was proven wrong. "So what does that mean? You are going to have to figure it out yourself." doesn't really sound like his belief of the flat earth was defeated.
Also, this is Jeranism, who has a history of doing a bunch of legit experiments, ending up proving globe every single time, admitting as much, then just going "well that's interesting", and keeping believing in flat Earth anyway.
Keeps believing or keeps griefing? I think he's smart enough to make these contraptions work and I bet he's smart enough to game the system for an easy buck as well. Because admitting as much probably means getting a real job.
As an impartial, uniformed third party, could they be trying to reach "true believers" and slowly walk them back on their wild beliefs? Almost Nnobody changes their mind by losing debates