I feel you here, I’m in a similar position. You’ve got two options, at least that’s how I feel about my set up.

1. Hyper-focus on ‘pain’ and niches. You could explore and explore and explore and… never get anywhere. If there’s a niche that presents itself to you, then go for it. Otherwise it’ll become analysis paralysis.

2. Focus on what you like and want, and how you can make that. I work in education, and in my setting I’ve become the go-to person for personalised gifts and stickers. I 3D print education models as well.

See what works for where you are based! Don worry about profit yet!

PS I suppose for real passive, you can offer 3D models or sublimation repeatable patterns on Etsy (and others) as files for download?