"What is the cryptocurrency for a long-term investment that will make me as rich as if I had bought bitcoin years ago?"
Nobody can answer! People have convictions, but no one knows for sure what will be the "best" crypto currency tomorrow. Any investment is linked to a risk, and on crypto the risk is enormous (do not let anyone tell you the opposite, an investment that is + 300% in a few years could have done -99.9% also). Who does not tell us that tomorrow, France, then Europe forbid the use of cryptocurrencies. Do you imagine the bitcoin / euro price?

In short, nobody has an answer to your question, except fools, liars and geniuses.