If you want big profits, choose coins with greater risk, and if you want to be safe, buy coins such as bitcoin and top 10 coins. You can make a decision depending on what you want to achieve, of course along with the risks.
You must understand that the coins with higher risks are mostly the altcoins with weak fundamentals. Most of the are just hype coins, they are not recommended to hold for a long time. They are surely not safe coins, they are likely the coins of hit& run projects. Actually, to get high profits, we don't need to choose the coins with higher risk. If we have good capital, we can choose the top coins with cheap prices. They are much better than the higher risk altcoins. MATIC, XLM, HBAR are some of top coins with cheap prices. However, for the main coin of our investment, it should be Bitcoin.

In General every market is risky to invest be it Crypto or Mutual funds or stocks. Just choose wisely, but seeing the utility of the token/coin and which VC is backing the coin is a good start. Do your own research. 
Of course, there is no safe market, all the markets are risky. That's why we need good knowledge, it will make use easier to decide wisely in choosing the coins. To make a research, we need sufficient knowledge! There is no way that a person who has no knowledge to do it wisely.