Constantly having to share your opinion on everything, despite not being asked about it. Being vocal about everything, and often over-reacting even if it's meaningless.
Other meaning could indicate towards "An occupational disease or industrial disease" From the line of work of YouTubers.
It usually means that you're losing any kind of joy from doing things anymore, and you always think how you can "turn it into content" or how you'd write a script or edit it
Thos guy has a YouTuber Syndrome, he just doesn't shut up