Is this somewhere on the horizon? I have no use for a DVR so don't want to pay the subscription (meaning I can't add m3u playlists on the Channels DVR server since it doesn't exist), but would also like a way to add the pluto TV m3u playlist to the $25 standalone Channels App on both my Apple TV and Fire Stick.
M3U playlist support is only available through the Channels DVR server. The standalone app can access the server, but it is not necessary. You need a Channels Plus subscription in order to use anything beyond live viewing (and limited timeshifting) with HDHR tuners.
The for hdhomerun app only works with live tv from hdhomerun.