In C, I could not find good libraries for basic stuff (dynamic string manipulation, variable-sized arrays, hash tables). I tried glib but it was much worse than C++'s STL.
It is entirely possible to write C-style programs in C++ (very few classes, globals all over the place) and so on, and at least for me, C-style software in C++ are much safer/easier to debug than C-style software in C .
In my experience the C mindset is to write those yourself. The lack of templates means that it's very difficult to write proper generic containers. You either end up with macro soup, void * soup or code tailored to your needs. Or a lot of the time a combination of all three.
But I'm like you, if I know that I'm going to need "advanced" data structures I'll pick C++ over C (or these days more likely Rust).
To go along with this, due to overloading and inheritance rules you cannot look at a small section of C++ code and determine what it does without reading up to the entire program.
I think that holds for any program written in any language. If the abstractions are confusing then it will be hard to read, be it layers of C macros, over-use of template programming or bad class hierarchy. BTW C++'s standard library is mostly functional (having roots in scheme), which makes it pretty easy to reason about.
It is entirely possible to write C-style programs in C++ (very few classes, globals all over the place) and so on, and at least for me, C-style software in C++ are much safer/easier to debug than C-style software in C .