Seems a lot of people want to get into the maker world but they often find themselves having problems coming up with an idea. This is what I do to figure out what I am going to work on.
First off, I'm not a big fan of trying to find a unicorn idea, one that will get massive funding and catapult me into startup stardom.
I'm a fan of finding low-touch SaaS products that have already proven the market for me. It's so much easier to get going when someone else has done validation for your idea.
If your goal is to build a product that can sustain the lifestyle you want, you're building a lifestyle business and there's absolutely nothing wrong with that. So seek out something that interests you and you can build something solo or with a co-founder.
My only biggest advice is to be passionate or at mimimum interested in the market. I had spent a few years building projects in different markets that I found myself not really having an interest in. This caused me to spend my time diddle daddling around and procrastinating until finally I just lost complete interest in the project.
You also don't have to be revolutionary in the market either, you don't have to absolutely shake it up and make your competitors clammer in fear of what you're doing. Just sliding into the market and getting a slice of that pie can be a damn good living for indie people. Hell some markets even the crumbs are pretty lucrative.
Your main advantage could be just that you are open to suggestions from your customers or that you just have damn good customer support.
Don't underestimate how much customer support can be for your product in itself. I switched from one service to another after 8 years purely because the customer support was superior.
So find that pie you want to get a slice of and start building. Be sure to ignore the big startup guys advice because they're in a different world than you, they are preaching what they only know, and that is getting funding. You want to build a business. One that is sustainable.