A few quotes from the Rabbi on 'Tzedakah and Healing'
in which he teaches that that Noah found grace, despite not being righteous in all his deeds, because he did not engage in robbery
"The school of Rabbi Yishmael taught: The sentence of Noah was also decided; but he was spared through the kindness of God due to the fact that he found favor in the eyes of God, as it is stated: “For I regret that I have made them. And Noah found favor in the eyes of the Lord”. And it says, above, "Rabbi Yoḥanan says: Come and see how great is the power of robbery, as the generation of the flood violated every precept, but their sentence to be destroyed was not sealed until they extended their hands and engaged in robbery, as it is stated: “For the earth is filled with robbery through them, and behold, I will destroy them with the earth” One asks, why Noah's sentence was sealed, since he was a righteous person? Should we say that he was not righteous, how then did he find grace in the eyes of God? One cannot say that this was because he acted as do those who seek to please others, for whom this might suffice even if the person is not upright. This could never be the case with God, who knows the heart's thoughts; no person who is not upright and worthy could find grace in His eyes. One must therefore say that Noah did not engage in robbery, which is the reason the Generation of the Flood's sentence had been sealed, since Noah did not deserve the Flood. The sentence was sealed even for Noah, because he was not righteous in all his deeds, but he found grace because of this fact, and could therefore become the remnant of the world. This is why RASHI, of blessed memory, interprets "righteous – in his deeds, without robbery".
Divrei Shalom, sermon, p. 84, HaHaim VehaShalom Publishing, Jerusalem, 1990