Honestly C and C++ code are the same. You can use C++ function calls and objects when needed and have everything else pure C. Don’t think of them as two completely different languages, C++ is more of an “object oriented framework for c” than its own language. That is a gross oversimplification but you get what I mean.

The problem with QT is that everything becomes a "QT app" when you start writing with QT. You'll end up using more of their types than the standard library, and getting a clean front-end / back-end separation is more difficult.

Anyways, C++ isn't just a superset of C; they're surprisingly different, and the best modern approaches are extremely so. That advice may have been true before 2014 and a bit until 2017, but it certainly isn't now.

sure but you can also use like java or python