Django on Render( and presumably a heroku) just works.
It's still much more work that just dropping in a Firebase url. Firebase can lead to poor design choices and come back to bite you, but hopefully by then you've already raised a few VC rounds and you're rolling in dough.
You have to understand a separate set of concerns. Spin something up on ec2, hook it into a db, configure https , figure out why it went down, etc.
You’re right though, once I build a complex front end I want someone else to do the backend.