Leveling up can take quite a while if you haven't bought any cards yet. But just in case, there's Rising Star Radio, with pretty good independent music.
They also have "Radio Evolved" once a week on their Youtube channel.
https://www.youtube.com/c/AtomCollectorRecords/videos
So if you want more of the music, check it out. But don't forget to start new missions.
My progress after one week: reached level 10 and earned 3273 Starbits.
Starbits are still cheap, 100000 for about 40 hive. That will buy 12 booster packs.
I will listen to music for a while and then decide if I buy.