how to add cookie blocking script to header

Hi

I am trying to setup CookieFirst (Cookie Blocking tool for DSVGO)
and need to add this to the Adsense code:

<script type="text/plain" data-cookiefirst-category="advertising">

tried it in template twig files. e.g.
adsense-managed-page-level.html.twig

but they don't seem to be loaded.

Any suggestions?

Thanks in advance