cmake-init-use-pkg-config VS cmake_format

You have to realize that the point of using CMake is not entirely about your project, but about downstream users who wish to use CMake as well. If you do not support clients using CMake (i.e. install a CMake package) you are forcing every downstream user to figure your requirements out by themselves, which even for a project with no dependencies is non-trivial: https://github.com/friendlyanon/cmake-init-use-pkg-config

See this example from the wiki. This one tries to use unofficial vcpkg package nd targets, then falls back to pkg config, then falls back to find_* commands. This is probably more than what you are asking, but you can put anything in the find module, even code that vendors projects, although I highly recommend against any form of vendoring (manual, git, FetchContent, etc). Vendoring only causes problems for packagers.

There's a cmake-format project with some linting features, but it's hard to add the checks to clean up the biggest CMake antipatterns because relevant solutions tend to be more opinionated in one direction or another.

Have you considered integrating cmake-format? It requires an extra dependency of course, but you can make it optional.