While yes, a zealot barbarian's lv 14 feature Rage Beyond Death does not protect it from disintegration, the barbarian's lv 11 feature, Relentless Rage, can prevent its HP from dropping to 0, which does prevent the barbarian from being disintegrated as long as it continues to pass a constitution saving throw to instead be conscious with 1 HP.

No, a zealot barbarian's lv 14 feature Rage Beyond Death does not protect it from disintegration. However, the barbarian's lv 11 feature, Relentless Rage, can prevent its HP from dropping to 0, which does prevent the barbarian from being disintegrated as long as it continues to pass a constitution saving throw to instead be conscious with 1 HP.

While yes, a zealot barbarian's feature to continue fighting even when reduced to 0 hit points does not protect it from disintegration, the barbarian's lv 11 feature, Relentless Rage, can prevent a disintegration by preventing it's hit points from dropping to 0 as long as it continues to make its con saves.

While yes, a zealot barbarian's lv 14 feature Rage Beyond Death does not protect it from disintegration, the barbarian's lv 11 feature, Relentless Rage, can prevent its HP from dropping to 0, which does prevent the barbarian from being disintegrated as long as it continues to pass a constitution saving throw to instead be conscious with 1 HP.