From my perspective that's possibly a partially-good thing. Don't do non-trivial things if you can avoid it. Projects should stay on the path of consistent practices, follow standards of packaging, and try to follow conventions that the build system lays out. Stay with standard libraries, avoid custom tooling when possible, etc. If what you're doing requires a boatload of scripting in CMake, you need a good justification for it, and if that justification is there then writing the scripting for the build system is the least of your concerns.

But yes it really is ugly once you get off the well beaten track of "here's my source now make a library out of it with a C compiler and a few standard options." I have a personal project I fiddle with that glues together verilator, fusesoc, CMake, a RISC-V compiler toolchain, and some custom scripting into xilinix vivado.. and it terrifies me just a little.