Fair enough. I don't think coding is a side gig kind of thing. You might find a few things playing music, but I don't think you can come at music with a side gig in mind.
If you're doing a side gig, do something that you love. Something that you wouldn't mind doing for free, but just happen to make money at.
I would only do coding if it would give you a promotion/ raise at work (I'm a pro software dev, the big opportunities out there for amateur coders is shrinking. Simple jobs have been sucked up by southeast Asians.)
Music to make money takes a lot of practice. You have play songs long after you're tired hearing them. I've played music as an amateur for free for many, many hours. It can be tough for a pro to make a side gig out of music. (I have met a lot of professional musicians who were unable to get any gigs and end up doing it for free for community events).
I think side gigs that will get you money will be:
1. part-time job
2. simple crafts that are time consuming (soap making, eggs, etc)
I've often thought about doing simple furniture building, but that's also something that comes with skill, time, and a lot of mistakes. I think you're going to find that in the side gig economy jobs that are typically thought of as fun do not pay/pay way less, and jobs that are more labor than craft will pay moderately well.
Building a craft (music, furniture making, art.) do not make good side gigs. Any money you make from those are bonuses on top of the love you already get from doing it. Though I'm not saying to undervalue yourself if you're good.
Doing labor that you enjoy (small agriculture, dog-walking, house contracting, lawn-care, tutoring), are going to be valuable gigs. These are gigs that are truly labor intensive, and people are willing/need to have these things done. Maybe learn how to tile a shower, put in hardwood floors, find people that need lawn-care maintenance. Real labor that maybe you wouldn't mind doing 2-7 hours a week.
The other types of side gigs I see out there are growing businesses. Typically though you'll need some money and investment knowledge to manage these.