You’ve mentioned that you don’t think that pitch wouldn’t take a redemption?
Yeah as much as I understand the want to redeem him & sympathise with him... he's ultimately too prideful to even consider a redemption or any kind of help in general.
GOC Pitch is redeemed only in death since he is (almost irreverisbly) possessed by the manifestation of nightmares and fear. He's much worse in the books anyway though, so no surprise.
ROTG Pitch has moments where we sympathise with him, the most genuine of which is when Jamie stops believing in him.
He has nothing to gain from false weakness in this moment (if he wanted to lean on their mercy I doubt he'd have fled the scene so quickly), and by being so openly devastated by it he's admitted not just to failure but to emotional vulnerability. In front of his strongest enemies!
His immediate reaction to flee feels like humiliation more so than fear for his survival (although that may factor in, I don't think it's the primary drive given their own reactions). The Guardians saw him in a moment of true weakness, he dropped the facade and he can't face their pity so he runs.
However, I think this is maybe one of the only moments of real, non-choreographed vulnerability. He spends the rest of the movie attempting to kill the Guardians, manipulate Jack and push the entire world into a permanent state of terror. So I don't feel overly bad for him when they push him about at the end. He tried to murder them!
The first potential moment of vulnerability for him in RotG is admitting to wanting to be believed in.
Which I also think is genuine and his true motivation, because at this moment I think it's highly likely that he hasn't even noticed Jack is there yet, and is just monologuing to vent emotion. His dialogue suggests he barely even cares that he's there.
And since he doesn't start to care about Jack until he registers as a threat, he has very little reason to want to manipulate him.
Pitch obviously knows that Jack is someone without believers, since he teases him about it. But that doesn't necessarily mean he's done his homework on Jack. In fact, it's an interesting worldbuilding anecdote - either he's inferring that Jack is a nobody, and belief is a point of social standing in the magical society, or Jack's desperate attempts to gain belief are well known amongst those with magic.
I think the only manipulation Pitch could be bothering to do in this scene is to use him as a witness to his defeat of the Guardians (Tooth in particular here) to spread fear to the rest of their society.
So the fact that his motivation "to be believed in" lines up perfectly to make us and Jack sympathise with him is purely coincidental, and therefore likely to be genuine.
However, the biggest source of sympathy for Pitch comes from the Antarctica scene.
Which is as far as I'm concerned, an undisputable attempt at manipulating Jack.
Pitch doesn't care about Jack at all until he starts to pose a threat. When Pitch finds Jack on the rooftops he starts to question why the Guardians would want to keep Jack around and is suspicious of both Jack and the Guardian's motives. Moments later, Jack displays a surprising amount of power - power that threatens Pitch but could also be an incredible asset to him should Jack turn to his side. It's only then that Pitch actually starts to care about Jack, when Jack is a threat he needs to neutralised either through recruitment (ideal) or some kind of restraint (destroying Jack's staff & throwing him into a pit).
If Pitch cared a whit about Jack or finding a likeminded individual who understands being alone, outcasted, and desiring a place to belong (family), then he would have targeted Jack from the outset. Before the movie even begins would have been perfect as Pitch is both aware of Jack's predicament & still building his own powerbase. But Pitch doesn't care about Jack before the movie's events, he doesn't care about him when they meet at Tooth's Palace, or even their second meeting on the rooftops in Burgess. He only cares when Jack becomes powerful.
Pitch comes across to me as narcissistic (superior, entitled, low empathy, etc), he wants to be the centre of eveyone's world. He wants to be impressive, powerful, capable, always in the right. What better way to prove this than to convince the only true threat he's facing to join his side? Jack is a challenge that Pitch thinks he can beat.
But Pitch won't chance losing, so he chooses the path with the highest probability of success, isolating and manipulating Jack.
He handcrafts a confrontation between Jack and the Guardian's that is guaranteed to result in Jack's isolation from the group. He separates Jack from the Guardians, his only support system, and terrorises him.
Jack is alone, disoriented, in the heart of Sandy's murderer's lair. Pitch casts doubts over Jack's suitability (something that Jack himself has already brought up) for the Guardians and uses Jack's desire to regain his memories against him. He frames Jack as selfish and thoughtless, not good enough for the Guardians.
But this is only the tip of the iceberg. Disorienting Jack, frightening him, feeding Jack's self worth issues and planting doubts on Jack's positive relationship with the Guardians. That's a bonus, a distraction from the real plot to frame Jack as a traitor to the Guardians.
All Pitch really needs to do is keep Jack busy while he destroys the Easter preparations, then send Jack back with his toothbox and voila Jack is the selfish traitor who is more interested in himself than helping the Guardians.
Jack wasn't even thinking of his memories until Pitch manipulated the toothbox to lure him in. And Pitch taking Baby Tooth hostage is a bonus that worsens Jack's reputation with the Guardians (now it looks like he exchanged her for his toothbox) and provides a failsafe blackmail should Jack refuse to join him.
This is part of the reason I don't like to pin the blame of the Easter fiasco on the Guardians. Pitch has set that up perfectly to drive Jack away from the Guardians and into his arms. Is it really their fault for falling for it? A little, but you can't say it wasn't convincing.
Then comes the grand finale of Pitch's ultimate recruitment plan - track down the vulnerable Jack now lacking any support system and play up the victim mentality. Something that Pitch likely does believe, but does he care about being lonely, or wanting a family? No, that's only added in to hit the bullseye on Jack's desire for connection. And Pitch himself reveals that he's lying.
Pitch only cares about getting what he wants, to be king of the world, to be the one in control, the smartest and strongest person around.
Which is exactly why he wouldn't want a redemption. He's only interested in himself, and anyone who doesn't bow down to him needs to get out of his way. The Guardians live to serve and protect the children, Pitch is actively preying on them to boost his ego. There's nothing you can offer him that's more appealing than being the biggest, smartest, best guy around.
Pitch's greatest asset is his ability to manipulate others. He doesn't try with the Guardians because they are (literally) guarded against that and know not to trust him. That's why they 180 at the end from showing pity to hunting him down and finishing him off.
He's a person, he has feelings of sadness and fear and pain. That doesn't mean he's not a liar or a murderer or an aspiring tyrant. Jack doesn't know that, so he shows a great deal of empathy towards Pitch, and as the audience's viewpoint we see Pitch through his eyes. We don't see the Dark Ages, we don't know Pitch's tricks. Because at the end of the day Pitch is emulating a lot of the standard abuser traits - isolate the victim, convince them they're nothing without you, reel them in with little shows of affection then use them for your own gain.
That's just my opinion though. I don't have anything against the interpretation that Pitch can ally with the Guardians, it's just not how I'm able to read the movie. His treatment of Jack is especially poor.
Interestingly, this is one of the few times where I kind of agree with Rufftoon? I don't consider her comics to be canon, but she kind of gives a similar interpretation in her comic Pitch Black:
Anyway, hope that was coherent? and thanks so much for the ask!