The 'Upload a video button' is a H5P widget and not compatible with the Moodle file manager. So you will need another tool to accomplish this.
One method would be to use the Lumi desktop tool to create a H5P content from a file on the desktop and then upload the H5P files via ftp to server file system. You would them be able to use the file system repository to add theme to the content bank. From the Content bank select Upload content and the File system repository will appear as an option in the file manager.
Another option would be to use the latest version of Repurpose resources content type plugin to import files into a Column content. This allows adding audio, image and video files to the column type with the Moodle file picker. From there the Audio, Video, and Image objects can be copy and pasted into other types. Unfortunately it does not look like you can paste into Interactive Video so it would have to be modified if that is what you need.