Add thumbnail to videos in SharePoint online via Highlighted content web part

[mezmerize17]

I am trying to create something like a playlist in SharePoint Online through the Highlighted content web part & tagging the specific videos via a document library, but I have an issue with adding custom thumbnails to the videos.

I've tried adding a image column to the library, but the video doesnt take it as a thumbnail.

I've tried using the Properties option for the file and have added the thumbnail but but when using the web part it still doesnt show.

I've tried embedding the video via iframe from the document library properties, it gave me an error.

I've tried via File Viewer web part but still no custom thumbnail.

To mention that i dont want to display on the site the videos as a list because then it will give control options to the viewers. Also, I cannot use youtube because of company permissions & Microsoft WebStream doesnt give me the result i want.

Any ideas?

Thanks in advance. Much appreciated.