Provide UserID via Tag Manager - what to push after Logout and any further pageviews?

Hello everybody,

When a user is logged in, I want to push the user ID into the data layer before the actual Pageview Tag is triggered.
The settingsvariable will use a data layer variable for existing UserIDs.

My question is what do I have to do to prevent the storage of the UserID on / after logout?

Is it enough to specify a data layer variable with the value of undefined? (not a string)
Because if the UserID value is not available for any other pageview, it should not be taken into account for Matomo.
But I am worried if Matomo safely excludes all actions for this logged out user.

Would it be enough to just fire on the same site, before the next pageview.


The page will reload and the dataLayer value is again undefined.