Please remove any reference of coercive language such as the second sentence in the language of the opt-out -> "You may choose to prevent this website from aggregating and analyzing the actions you take here. Doing so will protect your privacy, but will also prevent the owner from learning from your actions and creating a better experience for you and other users." Privacy is a choice that should be supported. The language could simply be -> "You may choose to prevent this website from aggregating and analyzing the actions you take here."
Or, offer the user the option to personalise the message that appears when using the shortcode.
Thanks for creating this issue @philipajane . Very appreciated. I will move this into Matomo core since it is not related to WordPress directly.
Had a quick look if there's already some plugin letting you do this on the Marketplace maybe but there is only https://plugins.matomo.org/CustomOptOut so far but this lets you only change CSS.