The approach to add rechunking after concat for arrow-backed arrays is correct and addresses issue #42357 for performance improvements. The implementation with the threshold-based logic and configuration option is well-designed.

However, there are 13 test failures across multiple CI/CD jobs related to DataFrame attributes. The failures show "AssertionError: Attributes of DataFrame.iloc[:, 0] (column name="data") are different" and "Attribute "dtype" are different". This suggests that the rechunking operation may be changing the dtype representation or other DataFrame attributes in unexpected ways.

The issue appears to be that when rechunking is applied, it may be altering dtype metadata or chunked array properties that tests are checking. You should investigate whether the .cast(pa_dtype) operation in line 1845 is preserving all necessary dtype attributes, particularly for complex dtype scenarios.

Recommendation: Debug the failing tests to understand exactly which attribute differences are occurring after rechunking, and ensure the rechunked array maintains full dtype compatibility with the original concatenated result.