Existing website with traditional tracking and usage of tag manager


I have a website with extensive traditional tracking (content view, event tracking). If I now integrate the tag manager into this page as described, it seems that both are not working together. Tags (PageViews, Events) are only measured in the Matomo Visitor Log when I remove the Basic Snippet.
Is it possible to use both ways of tracking together in one website and with the same Matomo Site ID?