Note, even Chrome on iOS uses the Safari rendering engine so Chrome on iPhones is not the same Chrome as found elsewhere.
My best guess is that when loaded using the <video> tag in the example above, Safari attempts to preload a portion of the video using the range: header. Unfortunately, it is a known issue that Large Media doesn’t support this header. There is a in-depth topic with a very clever workaround using service workers here:
There is an open feature request for this header to be supported but I’m not aware of it being planned anytime soon (and it is possible this support will never be implemented). For now, though, it simply doesn’t work.
If there are other questions about this, please let us know.