@ThoFin246
If I had to guess, it's because this avenger does give a sense of catharsis, while the twerp of redo of healer doesn't.
As much as he enjoys torturing those who wronged him and those under his care, Raoul still follows a moral code, which prevents him from harming the innocent, and he never forgets those who he's taking revenge for as well. On the other hand, for lack of better words, Keyaru is a selfish brat, who justifies his actions with sophism and a self serving sense of justice that only makes sense in his mind. Which would be okay were the story about his ascent to power and subsequent downfall. But that's clearly not the case, given how the author still portrays his actions as totally justifiable and the brainwashed princesses as better than how they were before.
The problem with Redo of Healer is that it's half assed. On one hand, the story seems to fancy itself an edgy revenge fantasy like this manga and Nidoume no Yuusha, but at the same time it also tries to ape Shield Hero, Arifureta and regular isekai-ish fantasy by playing the harem tropes as straight as possible. Which makes the contrast feel wrong to anyone but the most hardcore of self inserters.