We all complain about bad managers but does anyone here has a really good manager and steps up to take the responsibility of the projects when he/she is on leave?

Yes, I did. Until he got promoted to delivery manager and I was moved to another project.

My company don't have managers, we're 50 devs, 2 HR, and hell, everything goes fine

Yes.
I love my two managers. They're the best people I have ever worked with.

While not directly responsible for projects, my manager is great. He is the dev team manager (and not a dev himself), so he distributes and prioritizes the tasks and well, does all management magic. He has been working as QA beforehand.

@R2-D2 earning a shitton of money, everyone understand what you're talking about, fun.