Luckily, one can just ignore all the modern C++ shenanigans and use it as not much more than C with classes and some basic templates for generic containers. Those are too useful to give up.
For example, even though both Chromium and Unreal Engine are using C++, good luck finding basically anything high level in common. All of the naming schemes are different, the formatting is different, the high level libraries are unrecognizable. It almost feels like these projects are written in different languages.
Beneath all of that, they do make use of the same low level mechanics. A pointer is still a pointer, no matter what libraries you build on it. A stack allocation is still a stack allocation, passing something by a const reference is still the same, passing universal references to container templates is still the same. Includes work the same everywhere. And so on.
Basically, unlike most other languages, you want to have a solid understanding of these underlying mechanics so you can then quickly understand whatever high level libraries the project decided to build on top and hit the ground running using those. There's gonna be some kind of resizable array thing in every project.
But yes, you're basically starting over re-familiarizing yourself with the language on every large project or framework you explore. I've been using C++ for many years and never once used a std::string, since each framework has its own clearly superior string...