The plugin also needs to be enabled in plugins.js, usually by the game's creator using the editor.
You can paste the following line into that file to enable it for (most) existing RPG Maker MV and MZ games though, after pasting Qz_AutoAdvance.js into js/plugins/:
{"name":"Qz_AutoAdvance","status":true,"description":"","parameters":{}},
(Towards the end of the $plugins array, among the other plugins. It should be clear once you open it with a plaintext editor.)
