Consider deprecating old types API

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

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

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

No files, tests, or specific controller are named. Start by locating the controllers and the old types API, then review existing error-handling paths and related tests. Done means the deprecation scope and more descriptive controller errors are defined and covered by tests.

Written by the indexing model from the issue text.