Theme video-embed-iframe.html.twig by content type
That's not easily possible, not directly.

By default a media entity is going to be render cached on its own, that means the same media could be used in two different nodes with a different type and as long as they use the same view mode, it is only going to be built once. While you can get the current node easily on the detail page in preprocess and you could vary the rendered media by path, that will possibly result in a lot of variations and won't really work on views and other pages that display teasers of many nodes.

The easist way to achieve something like this would be to define two different view modes, use one from one node type and the second from the other.