The other answers have mentioned the competing solutions, but I thought I would add my experiences. I did some research into package managers and build systems for $WORK. We were greenfield so anything was on the table. These are my findings, YMMV.
Conan
Claims to support every build system but you need to write these Python scripts to tell Conan how your build works. Lots of magic, and easy to misconfigure. You also need to manage remotes, local remotes, etc. using conan create. We wanted something simple and this put me off. IDE integration did not work reliably (due to the Python scripts). I asked about reproducible builds and they said it is as reproducible as you want to make it. So it is not really reproducible.
https://conan.io/
Hunter
All packages are defined inside a single repository. You need to fork to add packages. Everything is driven by CMake. We want to deprecate CMake internally due to poor syntax, non-reproducible builds, and all the other issues you probably know already. Hunter offers reproducible installations of packages because you put Hunter in source-control, which is excellent.
https://github.com/ruslo/hunter
Buckaroo
Opinionated but simplest solution. No need to manage remotes or forks of package lists since all packages are just Git repos. We use GitHub private so this was a plus for us. We were a bit hesitant about using Buck build system, which they require. Turns out the Buck gets most things right (I used and liked Meson & Bazel in the past), and writing Buck files was less work than integrating CMake projects anyway. Also, and this was big for us, Buckaroo actually supports Java too. Maven support was hacky though. We were able to create iOS and Android builds from a single build tool / package manager. Documentation is poor but they were responsive to my emails. Needs more packages.
https://buckaroo.pm/
VCPKG
Similar to Hunter but from Microsoft. They don't have older versions of packages which might be a problem. Again everything is done in CMake, so builds get more complex and slower over time. I think VCPKG has the most packages of all solutions.
https://github.com/Microsoft/vcpkg
