Backupdirectory node damaged - New installation

Intermediate status:

Thanks @externa1 for the reply. All cleaned up. I have no RSAT Tools, because no Windows this time.

samba-tool domain demote --remove-other-dead-server=<server name>
samba-tool drs kcc

But i hat a problem with the internal SambaDB.
A very, very thanks at this point @scheinig for this post:

With this i was easy able to fix the DB.