Monorepo: Improve Error Management

[gabrocheleau]

As previously discussed in #487, stringified error messages are not a reliable solution long-term, and migrating to a more robust form of error management would be useful.

Relevant discussion: #1439

[holgerd77]

Update: latest state on this is a Lodestar-approach inspired PoC PR in #1910. It was decided to not do this along the breaking v6 releases but afterwards along a minor version release round.

No urgency on this, would still be nice at some point though.

[holgerd77]

Superseeded by #3712, will close.