To work on a normal laptop/Tv, I think you need to compress 4K to 1080p video first. Refer to this article and find a fastest 4K to HD video converter, see if that helps.
No problem playing 4K MP4 on my iPad Air 2. And to play all kinds of videos, I need QuickTime or VLC installed. I even use a third-party tool for re-encoding the video to 1080p when I'm feeling too lazy to deal with the crashing issue of the media player. <Dimo VCU Download>