good, bribe, servant
臧 centers on the idea of something or someone being good or worthy, but it also carries a darker sense of bribery and servitude, where goodness is transactional or enforced.
臧 is a phono-semantic compound: 臣 (servant, minister) suggests the meaning, while 戕 likely provides the sound. The exact historical development is uncertain, but the combination points to a servant or something stored/valued.
A servant (臣) is trapped inside a threatening outer shape (戕), forced to be 'good' through bribes or coercion. This captures both the positive and negative meanings.
For ゾウ, imagine a servant hiding a bribe inside a hollow statue of a Zou (elephant): Zou -> ゾウ, and the servant's 'good' behavior is bought.