I don't even entertain that conspiracy because it would mean she successfully faked it since 2017 without a single slip up while streaming an ungodly amount of hours. Also having stories about her condition that are very much in line with what other people experienced, having medical equipment go off on stream etc.
People saying she's faking it don't have a single argument other than "she made a lot of money". It's on the same level as "all VTubers are just dudes with voice changers".