Apple Intelligence & Siri pane is blank in System Settings - can't disable Apple Intelligence

This is the same issue as other people have encountered. I updated to Sequoia 15.6 a couple days ago. I previously disabled Apple Intelligence, but found it was active again after the update. I want to disable it again. But when I go to the pane in System Settings, nothing shows up. It wasn't like this before the update.

I've tried the usual workarounds people suggest – restarting in Safe Mode and rebooting (several times).

At times, when I try to view the pane, I see the error `Extension process Siri(2388) exited`.