Hi,
I found a article it shows a way to have a counter in WordPress:

https://www.meduo.de/2014/04/29/wordpress-anzahl-der-aufrufe-eines-artikels-anzeigen-ohne-plugin/

There are 3 questions.
Is there a way to copy the code into the function.php
and if yes:
it is possible to activate the counter in every blog article
Post_Views::increment_post_views(get_the_ID());
and read the counter
echo Post_Views::get_post_views(get_the_ID());

Thanks for Information.
Uwe