forgot the end quote on 'my-video'

Since you're using id my-video for the selector, you'd need to set the id attribute.

<%= content_tag :video, id: { 'my-video' } do %>

Is there a reason why you're wanting to implement this without Stimulus?

Keep in mind that "disabling" the "save video" option is a false sense of security with your video.  I actually did not disable it on these videos, but rather I am using Adaptive Bitrate Streaming on all of the videos. So, depending on your internet connection, it will auto select a m3u8 file which would best match your bandwidth. This will stream smaller video files of various qualities. You essentially "lose" the capability of being able to download the video file  since it's now just a blob reference to the m3u8.  However, there is a lot more involved with transcoding videos with Adaptive Bitrate Streaming. You can check out this video on how I accomplished it.

https://www.driftingruby.com/episodes/adaptive-bitrate-streaming-with-active-storage

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 ☒ https://www.driftingruby.com/episodes/service-objects-for-api-interactions-with-twilio might be a good episode to watch.

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 ☒ You can do some CSS hackery. It won't disable it, but will make it invisible.

.trix-button-group--file-tools { display: none; }