There is a wrong assumption being made by the OP. He feels that it is the young people who make mistakes for most part in the cryptocurrency sector. However, I have to say that the reality is very different. Look at various Ponzi schemes which involved cryptocurrency, such as OneCoin and PlusToken. Most of those who lost their money were middle-aged or elderly. I would say that OP should remove the "young" word from the title. Inexperienced users are more likely to make mistakes, and it doesn't matter whether they are young or old.
I agree and that's quite the right interpretation of the current situation. Young people are obviously more energetic and hence more attracted towards flashy investments but that doesn't mean young people are the only ones losing money to such schemes. I am not sure about what age group people lost money in the gigantic PlusToken scam but they were all inexperienced and naive because no Ponzi can pay you forever.
what's the best way to get high returns without taking risk?
The easiest or the least risky way of making the highest amount of money is to recognize your strengths because a dog trying to climb a tree will never succeed no matter how hard he works. A monkey on the other hand would do the same thing without any guidance or experience because that's what suits him and he's good at.