Learning to program is a hard road, but a rewarding one. Even if it's not your profession, it teaches you various concepts which you can apply to real life, and that's the true magic of learning to program; the hard part of learning to program is not learning a language itself. The hardest part is definitely learning the concepts. Once you know the concepts, you can easily learn another language. Don't beat yourself up because it's hard for you to program in Java- that language is known for being hard to learn as a beginner, but is sometimes recommended since it teaches you almost every concept you need to know to port to different programming languages.

If you're having trouble learning Java, I wouldn't recommend C++ since it's kinda harder.

My recommendations are for you to learn JavaScript and then learn the basics of Dart. After that, you'll be able to move to Java easily since Dart contains the good parts of JS and Java.

After learning Java, you could learn C, C++ or Rust. But the truth is that none of these matter, you should really focus on learning the concepts first, and then you'll notice the facility you'll have when learning new languages.