If you want to rerun a failed job, you can optionally enable the debug mode.

This mode adds the environment variable ACTIONS_RUNNER_DEBUG to true, but this has no effect to the Gradle output.
Instead, you need to change your workflow file and add ./gradle build --debug manually.

Expectation:
Automatically add --debug/--info (and maybe --stacktrace) when ACTIONS_RUNNER_DEBUG is true without the need to manually change the workflow files.