After the Esplora *and* Electrum variants have been merged, we should: - [x] Reconsider if we want a variant enabled by default, or if all remain opt-in via features. - [x] Clean up the error types and expose more of the underlying errors through sensible unified types (no wrapping) - [x] DRY up some of the sync logic/error handling, see https://github.com/lightningdevkit/rust-lightning/pull/1870#discussion_r1095927252