If you consider the prequels canon, Vader was a school shooter too, and a much bigger school at that.
A school whose teachers tried to murder the democratically elected leader of the Republic.
He was also doing all of this ostensibly to save the life of his wife and unborn child.
The situations are different. Sure we know Anakin was “a good friend,” but that then he was “seduced by the dark side of the Force.” On the other hand, we are told that Ben seemingly struggled with a darkness inside him from a young age (due to the “Vader in him”)
If Vader’s evil was transmitted genetically, Luke would have had a lot more of it than Ben.
…and was manipulated and seduced by Snoke specifically. So while Vader is implied to have turned because of a greedy quest for power,
And the whole Padme thing.
Ben is implied to have turned because he was exploited and possibly (in a way) brainwashed into doing so.
Ben also wanted to finish what Vader started, which I assume has something to do with this quest for power.
I’d honestly argue that Ben’s story is more tragic, and to see him die a full villain would just be plain sad.
They are both tragic for sure, but I was referring in Vader’s case to the classical definition of tragedy, where a great person makes an error of judgement and this has unforseen and calamitous effects.
https://en.wikipedia.org/wiki/Tragedy
“Aristotle wrote in his work Poetics that tragedy is characterised by seriousness and involves a great person who experiences a reversal of fortune (Peripeteia).”
“According to Aristotle, “The misfortune is brought about not by [general] vice or depravity, but by some [particular] error or frailty.””
Ben never has the chance to rise to greatness, so this definition doesn’t really apply. Of course it is still tragic in the general sense.
It also seems to me that the act of redemption is a return to the greatness already seen from a character. Since Ben doesn’t have this greatness, he cannot be redeemed. The only way forward is for him to commit to his dark path forever, or to grow enough that he understands the error of his ways.