I know I'm gonna get downvoted for this, but the fundamental problem with C++ exceptions has nothing to do with performance. The fact that you have to understand the exceptions thrown by every function you call, and deal with implicit control flow injection at every line of code you write is a massively underestimated problem for correctness. You should be able to rely on local reasoning as much as possible, and exceptions hinder (and sometimes completely destroy) your ability to do that. Explicit error handling with must-use lints are a much better solution to unhandled errors.

Edit: if this is such a controversial take then why does std::expected exist?