Digital Product Success Stories for Part-Time Hustles

I’m an engineer with a growing interest in marketing and tech, and I’ve been exploring ways to earn extra income by creating and selling digital products like Notion templates or simple SaaS tools. I’d love to hear from anyone who’s had success with this part-time what worked for you? How did you manage to scale your idea without it taking over your life? Any tips on finding the right niche or marketing approach would be amazing to hear about.