You are right! I’m using the Yoast SEO plugin. There you have the option (under “permalinks”) to omit the category base. There is a hint by Yoast, which I don’t fully understand:
“We suggest using FV Top Level Categories, if you insist on keeping this but do know that the feature is very error prone and not that important for your SEO.”
“Error prone” probably means, that I have to make sure, that there is no page with the same slug – no problem with that!
Cheers
Kai