There is QtCore that is more similar in scope to glib and only containers, json and a few more useful stuff. It's a sort of alternate C++ standard library.
Personally I wonder why people would choose today using C and Glib over C++ for system programming. I could understand why not Rust but for having to deal with glib in the past its so much of a pain.
As a mostly C and sometimes Rust programmer, I don't know why I'd ever reach for C++ instead of Rust these days. If I'm going to take on the mental complexity of these big languages, I'd rather have Rust's safety properties. (Not to mention, superior, portable, single-vendor standard library features — something C++ struggled with for a long time and probably still struggles with.)
Using C++ in moderation, without getting too crazy with classes, multiple inheritance, lambdas and other such things, works very well if you want to port a legacy C code base.
For a new project, there are many choices: rust, go etc.
