[Bug]: The union of errors can only be passed to ResourceCreate.

[MartkCz]

Describe the bug

The union of errors can only be passed to ResourceCreate.

Reproduction

ResourceCreate (OK)

ResourceUpdate (Error)

Checklist

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• The provided reproduction is a minimal reproducible example of the bug.

[markcowl]

• modernize the REST repo (for example, to use operation templates appropriately)