I did the same 3hour commute in NL, but a packed train is not the most comfortable for drawing. I've tried :D

Unless.... if you are a bit socially equipped, make quick portraits for people (in Procreate or physical) and share your social media handle with them... money will follow if you are (becoming) good at it.

These 3 hours can also be used to build an online presence (portfolio) for your 3d work. This is by far the most effective way to make money, if you'd ask me.

If not so social, listen/study art related audiobooks/podcasts. I can bombard you with a list, but it depends on your preferences, really. Let me know if interested.

Do you already sell 3d education on Gumroad?

Not sure my hints are helping...