Yes, that's what we do. Import -> HDMI

I confirm this works fine... except for something that sounds very trivial but which makes this Flipchart less interesting (all the rest is really good), namely that I just cannot take screenshots from the WM55H when connecting any Mac device either via direct HDMI or wireless with an AppleTV. I tested an AppleTV 4k, the one before in full HD, direct HDMI connection, from macOS Mojave, from macOS Catalina, from iOS 13 device, nothing works, it keeps telling me: the screen cannot be captured due to copyright restrictions.

It looks like everything that goes out from a Mac device is somehow protected by HDCP. Possibly the trick would be to find a HDMI splitter which supports HDCP on the input part but "forgets" to transfer it, some blog posts explains this works, but I'd need to test and first of all find a HDMI splitter doing that and supporting the full 4K resolution!