Files > 1GB can be copied via davfs2 from filsystem to Nextcloud but where deleted ca. 10 seconds later

Maybe that is the solution:

Annother possible solution:

(Google search for “BadRequestExpected filesize of bytes but read (from Nextcloud client) and wrote (to Nextcloud storage) 0 bytes. Could either be a network problem on the sending side or a problem writing to the storage on the server side.”