I'm probably biased, but you can build a Shopify app and have a very, very high chance at earning $1k or $1.5k per month within 12 months.
Here's a list of ideas that I researched last year, if it helps.
https://docs.google.com/spreadsheets/d/1Hnpcl1VAlPC9MuFvvsl2...
If you do decide to go this path, I've written a guide from my experience that might help you get things off the ground.
https://www.preetamnath.com/blog/shopify-micro-saas-growth
Whichever path you choose, all the very best!