While "best" is subjective, reliable channels typically offer frequent updates to combat "dead links" and buffering.
A raw M3U file with 20,000 channels is useless if you have to scroll for an hour. The best playlists have categories like: iptv m3u playlist telegram best
Reddit threads (r/IPTV, r/FREEMEDIAHECKYEAH) often have "Telegram Master Lists" that are updated weekly. Look for posts from the last 48 hours only. While "best" is subjective