Hey there The_ErsatZ_Planet,
Thanks for reaching out to the Apple Support Communities.
To get started, we do want to make you aware that this may be expected behavior, as "Just say Siri" is only available in certain countries and languages.
You can find this information listed in the footnotes at the bottom of this page here: Use Siri on all your Apple devices - Apple Support
Just say Siri is available in United States, Australia, Canada, and United Kingdom.
If you are in one of the supported countries above, let's ensure that your iPad is updated to the latest version iPadOS 17 with the following steps, and see if the issue persists: Update your iPhone or iPad - Apple Support
Keep us updated on what you find.
Take care.