You can't uninstall it, you can only disable it. That's because it's a built in plugin, those can't be disabled without breaking incremental upgrades (which personally I don't use anyway).
And like many others here, my corp explicitly forbids ANY use of ANY 3rd party LLM technologies at work. It's a disciplinary matter. So JB forcing something on people that means they could potentially lose their jobs for using IntelliJ is just monumentally stupid.
There is a workaround which is to manually delete the plugin, see https://youtrack.jetbrains.com/issue/LLM-1760/Can-not-remove... But as above, that breaks incremental upgrades.