session()->stop() not destroying data

To clear the current session (for example, during a logout), you may simply use either PHP’s session_destroy() function

Nope!

This part was due to my error. The session_destroy() function provided by PHP does work. However, $session->stop() does not. I upgraded to CI 4.3.4 just to make sure this is still relevant. This is on a system still using PHP 7.4.

It looks like this may be a long-term problem. There's an old Github issue about this. That issue was closed with the claim that "it's all working as it should" (with data still present after stop()) despite a prior statement from the same person that the data "shouldn't be" still present.