Investing in altcoins is risky, they themselves take this risk
You can reduce your risk by investing in trusted and well-known altcoins. As there are lots of fake projects, don't buy a relatively less trusted coin unless you have certain knowledge about them.
Read this post and its true how small investor are losing bitcoin by investing in other coins.
You can buy 8000 tokens in 1 USD when price of bitcoin is 8000 USD but if bitcoin price will rise to 16000 USD then you can buy 16000 tokens in same price. Now all token price does not move according to BTC price,it will drop 20-30% without any sign of drop, but when you will compare with bitcoin you will find that you are in loss.
https://cryptomaa.com/btc/how-small-investors-are-losing-bitcoin-by-investing-in-altcoins/It's true that the some people are losing money investing in the coins which are related to fake, scam project. But your analysis in the link is not justified, as you have considered that the altcoin value to be fixed. You can find lots of coins in the market moves exactly opposite way that you have explained. So it will be false to conclude that the small investors are losing money by investing in Altcoins.