Not everything is visible in normal server side logs, especially if they have a lot of client side actions.

Then create a custom endpoint that records those client side interactions in a database.

So... client side analytics? Like Google Analytics?

Obviously not a third party like Google, especially not Google.

Inform your users honestly and do not hide things. Make promises about tracking data usage and stick to them. Tell them the truth and give them a choice. Stop acting like you got something to hide and do your tracking yourself.