Whilst I have not tried it myself it appears Channel 4's live service can be streamed via the TvPlayer- there is app for Samsung Tv's but information states only compatible with 2016/2017 models.
(basic service is free but charge for some premium channels if desired)
Not through the All4 app, however, I figured a workaround. Open the internet browser on the TV, and go to the channel 4 site. Signing in is a pain using up down left and right, but you can stream live from there. 😊