> I don't want to write all of my backend in C++.

The difficulty of C++ is way too much over rated. Most mediocre projects can be written with basics of C++ (that everyone can learn in less than 3 months).

We could have lived in a way performant world, if people would stop horrifying beginners about difficulties of C++/Rust/...

Go talk to a beginner, the moment you say anything about C/C++, the first thing they mention is, what do you do for buffer overflows? They don't even know what it is, but they are worried about it.