I would only buy Bitcoin. Bitcoin goes through a halving cycle, and historically it prices have always followed a predictable path. Right now is the perfect time to buy Bitcoin, as it just fell because Elon Musk sold a lot, and that spooked the markets. However, in the next two years, it should double to triple in value. There was a thread about this that I started a while back.What is the opinion of people on crypto currency ?
That being said, it's very risky, and should only represent 5-10% of your portfolio at most. Also, you need to know when to pull out. Holding on too long will expose you to huge losses, and it will be too late to recoup your money. You will have to wait until the next cycle.
Crypto is basically one big ponzi schem. But that doesn't make you can't make money. It's price is heavily manipulated by a few "whales" who hold much of the coins. There isn't any real value to crypto, just like NFTs. However, Bitcoin does have practical applications, and of all the cryptocurrencies out there is the most stable and likely to hold its value or appreciate long term.