Give me a starting point similar to CPAN, PyPI, crates.io. The One
Place on the Internets where I go
when I need to find a C++ library.

For now you can go to <https://conan.io/center/> and <https://vcpkg.io/en/packages.html>. For the future I am actively working on <http://wg21.link/p1177>.

For the rest of the thread.. Ask yourself what your goals are. And what already exists that meets, and doesn't, your goals.