Use Nextcloud desktop-client with baseauth

For security purposes my provider uses base auth of the webserver for authentication, before enabling php.
The newest version of the nextcloud-desktop client now wants to open the webpage in an embedded browser and stucks there.
I can use the an older version of the desktop sync-tool and it just asks for username and password.
It is also possible to use the new client with a version of owncloud, when I want to connect to the server the desktop-client just asks for my password and username.

Is there a way to force this behavior ?

Thx for your Help.