Customer onboarding automation for new users

I launched a side project and users sign up but don’t activate. I’m manually emailing each one tips based on what they clicked. I have a day job and can’t babysit onboarding.

I need new signups to get a personal checklist based on their role, nudges based on product usage, and alerts to me only if they’re stuck for 48 hours. If they hit a key milestone, ask for feedback. I want it to feel like I’m there without actually being there. What’s the lightest way to automate this?