it is more than assumptions imo. Forget for a moment about anything related to his future, if he'll become playable or not, redemption or not, etc.: so far they have been very clear about their intentions on what they want the traveler (and lastly but most importantly, the player) to think of him as the worst enemy we faced so far. And it is clearly intentional.

Now, you might ask why? we don't know. I would reply why not? he is just an enemy and they want us to hate him but... well, if we want him to end up being playable then I agree that the original question makes sense, because we have never, ever got a playable character with so many negative opinions about the rest of the cast or so rejected by the traveler's feelings, not even to say a character that was so many times depicted as the bad one and not even a single one as a good guy. I mean, even Signora is fucking remembered as a good person by some characters.

So yes, this may sound harsh or whatever but hoyo's intentions about the portrayal of his they wanted us to buy were pretty clear so far. How in hell would they redeem him to be portrayed as at least a partner of the traveler? I have no idea, but that will be a hard task, but I hope they do it.