Background

This is a follow-up to #1843 — specifically, my comment #1843 (comment) about using:

#[serde_as]
pub struct Sha256Digest(#[serde_as(as = "Hex")] pub [u8; 32]);

instead of copy-pasting #[serde_as(as = "Hex")] everywhere.

It turns out this introduces a cascade of required changes, so I split it out into a separate issue (this one).

User Story

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Acceptance Criteria

Reduce usage of #[serde_as(as = "Hex")] introduced in #1843.

Resources & Additional Notes

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