C++ doesn't have low barrier of entry, I almost quit programming as a teen because of C++.
This used to be even more true previously than today. Nowadays, there's stuff like vcpkg, and tons of resources, but I still wouldn't call it straightforward compared to something like nuget or cargo.
It tooke me more time to figure out CMake than entire other programming languages.
† Default means just that, neither Rust's own compiler nor the Linux kernel need the cargo tooling, but these projects both have actual toolsmiths to maintain their build infrastructure and your toy program does not. There should be a default which Just Works at this small scale.
APT/dpkg/yast/rpm/pacman/... ?
Make is very simple, you don't even need a makefile. Just type "make main" for main.cpp and it works.
In reality it matters what you already know, and whether you want to understand deeply or are just interested in enough surface understanding to write software. There's a reason C++ has an entire book about its many, many types of initialization for example.