Verified that DW does not work for me either. Checking the hls.log provides the links being used:
at=2021-07-30T07:27:25.513014539-05:00 tag="dw" action="parseMasterPlaylist" url="https://dwstream4-lh.akamaihd.net/i/dwstream4_live@131329/master.m3u8" status="200 OK" time="15.304521ms"
at=2021-07-30T07:27:25.53094447-05:00 tag="dw" action="fetchMediaPlaylist" url="https://dwstream4-lh.akamaihd.net/i/dwstream4_live@131329/index_1_av-p.m3u8?sd=10&rebase=on" status_code=200 status="200 OK" content_length=21204 playlist_count=180 target_duration="10s" time="17.673288ms"
at=2021-07-30T07:27:25.53350267-05:00 tag="dw" action="close" time="631.897µs"
Manually fetch the playlist from the "fetchMediaPlaylist" line:
curl -sL "https://dwstream4-lh.akamaihd.net/i/dwstream4_live@131329/index_1_av-p.m3u8?sd=10&rebase=on" | head -20
#EXTM3U
#EXT-X-TARGETDURATION:10
#EXT-X-ALLOW-CACHE:YES
#EXT-X-PLAYLIST-TYPE:VOD
#EXT-X-VERSION:3
#EXT-X-MEDIA-SEQUENCE:162669412
#EXTINF:10.000,
https://dwstream4-lh.akamaihd.net/i/dwstream4_live@131329/segment162669412_1_av-p.ts?sd=10&rebase=on
#EXTINF:10.000,
https://dwstream4-lh.akamaihd.net/i/dwstream4_live@131329/segment162669413_1_av-p.ts?sd=10&rebase=on
...
The playlist type of VOD shows they are grabbing the wrong stream (and the player will not play or even generate exceptions in the DVR with VOD). Am guessing DW changed their webpage and whatever HTML search pattern Channels uses now grabs a URL to a static video assets (VOD). The M3U you referenced is indeed the correct live-TV stream.
It is unfortunately that Channels does not seem able to XMLTV export a single channel (or at least I have not figured out how). Otherwise, it could potentially be uses as import epg data for work-around solutions like this.