Hi
Your solution works at my side, many thanks @welstand. I am on Big Sur 11.5.1 running Zotero with Better Biblatex mdnotes and zotfile basic configured , exported bib as better biblatex. I tried also JSON, but better bibaltex works here.
My current Literature note title template shows:
}Z-{{entry.author.[0].family}}{{entry.author.[1].family}}{{entry.author.[2].family}}{{entry.author.[3].family}}{{entry.author.[4].family}}-{{title}}
Where }Z is a category-placeholder, which I have to set manually after note creation (}b=book,}w=website,}a=article) . Each increasing number with {{entry.author.[0].family}} will take the next lastname out of the entry.author array I think. That gives me 4 lastnames and the title of the reference, for me its ok.