Write-protect shared contacts?

Hi Community,

am i right the it’s not possible to write-protect shared contacts (address books)?
I share an address book with other nextcloud users. In contact settings i did not set the option “can edit”, but all everybody can edit or delete my contacts.

I found a post from 5 years ago, with the same problem but no answer.

Did anyone got the same problem or, much better, a solution?

Thanks a lot.