I'm maintaining a C++ web application written 12 years ago. It's not pretty. I cannot describe the difficulties even an experience C++ developer would have in trying to understand and maintain it.
Fortunately modern C++ is pretty good. We've managed to tack on a legacy compatibility layer via the Boost libs to give us a Python wrapper. It's still running in production and is still pretty useable.
However, C/C++ still requires a fairly high cognitive load for a diminishing return, IMO. There are other languages that are easier to understand and maintain whose implementations are getting increasingly better at competing in areas where C/C++ used to be the go-to choice. There are simply fewer cases where I will reach for C++ these days where it used to be the only choice.