Alan SP said over 1 year ago on Streaming Videos with Active Storage :
Thanks, the second one worked with a minor typo fix (missing curly brace):

<%= content_tag :video, { 'data-video-target': 'player' } do %>

Unfortunately, I'm getting no video or console errors still.

For what it's worth, I did get it to work with the plain js block from the videojs site:

<video  id="my-video"  class="video-js vjs-big-play-centered item-video"  controls  preload="auto"  data-setup="{}">  
  <source src="<%= url_for(@item.attachment) %>" type="<%= @item.attachment.content_type %>" />  
  <p class="vjs-no-js">    
    To view this video please enable JavaScript, and consider upgrading to a web browser that <a href="https://videojs.com/html5-video-support/" target="_blank">supports HTML5 video</a>  

Let me know if there's anything else worth trying. Cheers.