I thought this would work - and it does! Here’s how to add radio channels as Live TV:

• From the Jellyfin homescreen menu, navigate to the Dashboard
• Click the Dashboard menu button (three stripes at the top)
• Go to Live TV
• Click the first (+) button to add a new tuner device
• Choose “M3U Tuner”
• Select your local .m3u file or paste a URL
• Click Save
• Go back to the homescreen of Jellyfin
• In the menu, click Live TV
• Switch to the tab called Channels
• If your .m3u file works, you can select any channel it contains from here.

You can even add a custom logo for each channel:

#EXTM3U
#EXTINF:-1,Channel 1 tvg-logo="https://link.to/logo-ch1.png"
http://liveradio.url.channel1.fake:8000/channel1-is-fake.mp3

#EXTINF:-1,RadiOmega tvg-logo="https://linking.park/logo-radiomega.png"
http://liveradio.nope.omegalive:8000/y/radiomega.mp3

And rank them in the list by changing -1 to positive values IIRC.