I've found the real 'one true solution' for my needs to be conan + meson. Conan includes a build script that supplies pkg-config files to Meson for dependency handling, and with conan you can use the gigantic repository of packages along with bincrafters for an even gigantic-er repository of packages. I have not yet found a package I needed that wasn't on either conan center or bincrafters. And on Linux I can download the source to build if I really want to, but on Windows I'm happy just downloading the binary .lib files. And it's so easy to use. cd build && conan install .. && conan build .. is all you need to download and compile everything.
Before this setup I used vcpkg with cmake and I'm never going back to that. Yet before vcpkg I used ExternalContent, which I would also never go back to. Ergonomics are extremely important with this kind of thing. I think that's why cargo is a huge hit in this space.