Hi LeRoy

Results from

# apt-get update

Mostly successful, threw the following errors:

Err:11 http://ppa.launchpad.net/kdenlive/kdenlive-stable/ubuntu focal/main amd64 Packages
  404  Not Found [IP: 91.189.95.83 80]

You need to take the kdenlive ppa out of your apt config. Adding Ubuntu repositories to your Debian is a good way to break your system.

...

E: The method driver /usr/lib/apt/methods/https could not be found.

...

E: Failed to fetch https://download.jitsi.org/stable/InRelease  
E: Failed to fetch http://ppa.launchpad.net/kdenlive/kdenlive-stable/ubuntu/dists/focal/main/binary-amd64/Packages  404  Not Found [IP: 91.189.95.83 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.

Results from

# apt-get install kdenlive openshot flowblade lives olive-editor pitivi

Mostly successful, threw the following error:

E: Unable to locate package olive-editor

Remove the ppa first and try again.

Results from

# apt-get install lives-plugins

2 newly installed

This would have installed lives and lives-plugins. Nothing else