Also, I have the belief that Bitcoin will keep breaking new ATH forever. Should I leave my Bitcoin forever without selling it or set a goal that I have in mind and when it reaches that goal I sell and take my profits?
This is something that there has been a lot of debate among Bitcoin holders on this forum. Many people believe that selling Bitcoin for USD in the short term when profitable is an unwise action, and they believe that it is not Bitcoin holders. And they believe that Bitcoin holders must hold for a long time, at least 1 cycle (4 years). There are also opinions that their holding of Bitcoin is just an investment, and since it is an investment, there would be a specific profit-taking plan. They don't care how long they hold, as long as they meet the target they initially set, they will sell. For a few, holding Bitcoin is like a religion for them, they have no intention of selling, only buying more.
I think there are many purposes in buying and holding Bitcoin, it is important that you determine what your goal is? Don't be influenced by other people's opinions, because each person's investment situation and position is different.