If it works in managed resources on the same device and browser, then it should work on the dashboard as well as they display the media resource the same way.
One difference on the actual Media Tile is if you have the Autorefresh enabled. When the media item first loads, it’s exactly the same as the Manage Resources tab… but once the refresh interval occurs, it will append an arbitrary URL parameter as a cache buster technique.
Since you mentioned that you already have the setting to allow mixed content enabled in Fully Kiosk, I would pay particular attention to the Chromium 111 bug mentioned above as many modern web browsers are based on that… check the reply above about using nip.io as a workaround.
Edit: If you are using Blue Iris, you might also check this post about embedding Blue Iris streams in a much more efficient way.