Well why the hell did Vader deserve redemption?
He didn’t, we tolerated it because Vader was well written and it was easier for us to feel that his love for his son was enough to make him turn back.At least Kylo had layers, some obvious conflict.
Mm, this is an odd one. Vader had many more layers than Kylo. Vader was always in conflict, he was a slave to the dark side. Kylo chose to be the monster he became and I honestly don’t think the movies gave us reasons for him to have let darkness grown inside of him.
The difference is Vader got three extra films to explore his fall, where Kylo starts off bad.