The first Aquaman film includes unresolved story threads that prove Ocean Master should be redeemed in the sequel. With James Gunn developing Warner Bros' new DC film universe, the old DC Extended Universe will end with Aquaman and the Lost Kingdom. The Aquaman sequel will feature a team-up between Arthur and his brother Orm and will be the DCEU's last chance to resolve incomplete character arcs. Ocean Master's unfinished arc is one story that shouldn't be neglected.
Source:https://www.cbr.com/ocean-master-orm-redemption-aquaman-2/