* “Weird bugs”: I suspect CMake wasn’t finding the version of Python you wanted because your find_package command was just finding a different version first. This is much easier to debug today by using —-debug-find-pkg=Python, which will print all the places it searches Python for and what it finds. You can then modify your find_package invocation as appropriate to find the Python you really want to use.
* Messy structure: yes, unfortunately I’ve also seen my fair share of nightmare-inducing CMake files.
* Opaque process: here I actually quite disagree. In my experience I’ve found it super easy to modify things like compiler flags (just use target_compile_options, or add_compile_options for directory wide options). And what made a big difference was using Ninja as the generator (I also use Ninja on Windows), which makes it super easy to view the final compiler commands that will actually be invoked. CMake is essentially a compiler that emits Ninja on the backend, and several times it’s been invaluable to confirm in the generated Ninja code what is actually being invoked.
CMake is definitely not perfect, but it’s much better than what it used to be! It’s ultimately a perfect match for C++ (both extremely powerful, configurable, hamstrung with decades of backwards compatibility, terrible ergonomics, etc.).