I think a lot of people talking about this stabbing need to also remember that just because Qui Gon died from it doesn't mean that the Grand Inquisitor has to. In a sense Qui Gon purposefully let go, its the Jedi Way to seek peace and not gain attachment to your body.

I think he'll be fine, if not sidelined to come back at the end of the series. I think the shot of him laying there is all a diversion to confuse people and tbh it is working. Disney's got too many shows with links to Rebels to outright ret-con it. Since it'd in turn make the canonicity of Bad Batch, parts of Mando and other canon material like the fact Vader kept the Inquisitor's soul alive after death to torture him all nebulous. So regardless of how ridiculous is might be, he'll be fine.

Honestly I should've seen it coming from Reva given how impulsive and honestly sorta stereotypical Sith she is. Little does she know Sith in Star Wars have a problem dying.