Ultimately, the Good Omens show never committed to anything.
It didn't commit to a tragic ending or a happy ending. And it didn't really commit to a true bittersweet ending because, imo, that requires character continuity. The characters have to know what they've lost (and gained) to make it poignant.
It didn't commit in any way philosophically, which has been explained very well by many eloquent people, so I won't add more.
It didn't commit to A&C's relationship. We never learn whether they enjoyed the human love rituals they tried and wanted more, or not. We don't get a clear answer about when they each fell in love or learn what the nightingale meant to them.
It didn't commit to a clear explanation for the discontinuities that were teased.
It didn't commit to a characterization for Aziraphale. He became whatever would generate maximum drama in a given moment.
It didn't commit to a characterization for Crowley either, but at least he got to be the only "real boy" in the old universe, the one person who actually mattered.
The show didn't need to commit to all of this, but it did need to commit to something.
