I've found some of these streams change URLs after a few weeks, so the m3u needs to be updated to match.
I don't use hlstube but a similar youtube-dl docker. Here's a YouTube tip: if the stream keeps changing but the YouTube channel it's posted on remains the same, you can append "/live" to the channel URL and it will redirect to the latest livestream. Unfortunately channels with multiple live streams like Sky News will not always redirect to the same stream.
Example: https://www.youtube.com/c/NBCNews/live