The video is a simple MP4. It works if I open it in it's own tab in Brave and I have checked and verified that Brave itself it not blocking it.
The server does support "Range" Requests and the video works in Safari.
<video playsinline autoplay muted loop poster="image.jpg" class="w-100">
<source src="video.mp4" type="video/mp4">
</video>
The poster does work and it shows in brave but the video will not play.