to everyone who do not wish to use AI (good idea), remember that you not only will need to disable Siri, but also all the various Siri & Apple Inteligence crap everywhere now.
On early tests we could observe that, for example, just disable Siri and leave Siri and Apple Insteligence enable on Apple Mail, would still make Siri read the emails and give email recomendations etc. This on 27.1 on Ipad/Iphone.