C++ is fine, but it's insanely slow to compile.
I generally like C++, but I could trade anything to make it faster to compile, and most of the time, I just use a small subset of C++ that I feel okay with.
Modules support was added recently, and I don't think most libraries or cmake support it yet, and I don't really see tutorial about good practices for modules, especially when it comes down to speeding up compilation.
Also modules do not really speed up compilation that much, apparently, or I have not seen benchmarks, maybe because modules are not well supported yet?
Modules are great in theory, but I am not sure they are usable in 100% of cases, especially with all the existing code that is out there?
PImpl doesn't need to have a performance hit as you can implement it with a local fixed-sized buffer that's not heap-allocated.
You can also design your C++ codebase exactly as you would in C, so there's literally no reason why you'll need to recompile more in one language compared to the other.
A quick google "c++ grammar" will give you clues that C++ is not you average language. Templates are also turing complete, and probably not trivial to parse.
Of course I am not talking about C++98, but C++14, 17, etc, which add significant stuff.
There are definitely advantages to simpler tools, you can streamline development and make people more productive quicker. Compare that scenario to C++ where you first have to agree the features you're allowing and then have to police that subset throughout on every PR.
Personally when I initially learned C++ back in 1993, with Turbo C++ 1.0 for MS-DOS, I hardly saw a reason to further use C instead C++, other than being required to do so.
Unfortunately adhering to modern tooling is always a quixotic battle, even when they come for free on modern FOSS compilers.