There are things in the C++ standard library that are not very well designed, yes.

For instance, erasing from some containers causes undefined behavior if iterators that were created before the deletion continue to be used.

Some of the various smart pointers for managing memory are not so smart; they have been redesigning new ones and deprecating old ones so many times now. It used to be "your code isn't exception safe: use auto_ptr, you dolt!". Then, "you idiot, don't use auto_ptr, use this instead" and so on.

You can avoid all that by defining your own classes that do just what you need, use only the safe stuff from the standard (like the aforementioned strings) and write yourself a perfectly memory-safe, leak-free C++ program.

Even the modernest pointers unique_ptr and shared_ptr are dangerous (use after free/move and, e.g., ease of data-racing in the data, respectively). The problems with them are relatively fundamental to C++ and its idioms. The classes you define will need to avoid using fundamental C++ features like references too: anything pointer-like can lead to problems (including `this`)

The "you (and the standard library, including the completely new parts) are holding it wrong" defence is tired, when it is so ridiculously easy to do so: it is okay and important to acknowledge that a tool is powerful but also has a pile of hard-to-avoid sharp edges.