Save videos to your own server (WebDAV)

Nextcloud, ownCloud, Synology, a Hetzner Storage Box or any WebDAV server. Studio plan.

In Connections, open the My server tab, pick your server type and the address pattern is filled in for you:

Nextcloud or ownCloud: https://your-host/remote.php/dav/files/USERNAME/ with your username in the path, and an app password from Settings, Security.
Hetzner Storage Box: just https://uXXXXXX.your-storagebox.de/ (or the sub-account name) with WebDAV enabled in the Robot panel.
Synology NAS: the WebDAV Server package over HTTPS, https://your-nas:5006/.
Other: the full https address of a WebDAV folder you can write to.

Choose a folder name (default KolReel) and press Save and test connection. KolReel signs in, creates the folder if needed and only then stores the connection; the password is encrypted and used only for uploads.

On a finished video press Save to my server: the main file and the vertical version are uploaded, named by title and date. Open on my server opens the folder listing, from where you can download the files. Plain http and private network addresses are refused.