For Unreal Engine, I am still going through this Udemy course. It covers a lot of basics in a very approachable manner.
Another resource that I keep coming back to is A Tour of C++ (available legally on the isocpp website). Whenever I have a doubt about anything related to C++ it’s one of the first places I check. It’s pretty great if you already know how to program but aren’t an expert in the C++ language itself.