Improve error messages in config

**Problem**
When working with core, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

Start by locating the config and core error-handling entry points mentioned in the issue. Review the current errors and identify where additional context can be added; done means the relevant failures produce more descriptive messages that improve debugging and maintenance.

Written by the indexing model from the issue text.