There are many ways to invest and must be smart. First, you need to fully understand what you are investing in, no doubt Bitcoin is the best but Altcoins could be a source of good investment as well if prioritized and watched. Bitcoin is the only stable Crypto I know and when playing with Altcoin it needs to be on short-term basis as many are not decentralized or fully decentralized as claimed.
Of course, we must invest in a smart way. This surely requires good knowledge and deep understanding about what we are investing in. Have a proper learning and got some experience related to the investment should be very recommended. It will bring a positive influence to our capability in the investment. When we have good knowledge, we can be wiser and more careful in making any decisions related to the investment.
You're wrong if you think Bitcoin is a stable crypto. Bitcoin has a high volatility, it is not so different with altcoins. But Bitcoin is more established than altcoins, it has everything to survive a long time in crypto industry. However, it doesn't mean altcoins are bad options for investment. The top altcoins are also recommended for investment. They have good fundamentals and have clear future. I invest in the top altcoins both for short and long term investment.