OP, what is your background to be in the position to build this? I've been itching to build or have an idea to make something complicated but only true thing I kind of know is building API and integrating with React application.

How were you able to deduce complexity into workable item/task to take 'I will alternate to Heroku' into fully functional open source project?

I haven't really use Heroku, so to figure out 'feature to be implemented', I would start with pricing page. I am sure my approach is flawed here.