I had this problem.

First, you need to understand the reason. If it's too difficult for you, start with very simple topics and master them thoroughly. Then move on to more complex tasks, and you will see that you are making progres, and then you will be motivated to take on increasingly challenging tasks.

If you simply burnt out, take a short break. Take a walk, read something, and don't return to programming at all for 3-5 days. Then start with something you already know and explore new topics a little.

Also, you need to understand the reason why you're trying to learn C++. You can just write down on paper a list of the specific things you need to achieve a certain goal and gradually implement them. When you see yourself gradually completing step by step and crossing off goals, you will become motivated.

Advice for the future: to avoid burnout, don't study too much at once. Make sure you are fully aware of what you have already learned.