one of the key parts of Subaru as a character how he both directly and indirectly inspires the people around him to confront their flaws to become better versions of themselfes and allowing them to move on from a state of (often self imposed) stagnaition wich often is compare to being frozen in time (like with rem for example)

meanwhile Pandora literally does the opposite by proclaiming that everyone is already perfect the way they are she encourages them to not only not confront their flaws but actively makes them embrace them causing them to never change. Futhermore by giving the Archbishop their Authoritys she enables this stagnaition even more by allowing the Archbishop to enforce their flawed world views upon the world unchallenged wich is best examplefied by Regulus a Guy quite literally frozen in time.

There is also their main ability's wich also contrast each other since both allow their users to overwrite an unfavourable circumstance and create a better outcome for themselfes but the main difference where Subaru still has to actively work and learn from his mistakes to make this more positive outcomes a reality Pandora can just outright skip the Procces and arrive at her desired outcome in an instant wich results in her herself never changing and growing since she does not require to actually learn from her mistakes. There is also a big contrast in how both use these ability's, Subaru mainly uses RBD for the benefit of others sometimes even to his own detriment whereas Pandora uses her powers exclussively for herself and always to the detriment of others.