First, low-risk money and debt funds are unlikely to lose money, but their returns are not high. For example, Alipay's Yu 'ebao is one of them. If it is regular, it will be higher.
Second, funds that invest in bonds and stocks in proportion have moderate risks and relatively large gains and losses.
Third, stock funds fluctuate greatly. When the stock market is good, they can earn twice as much a year, and when the stock market falls, they lose a lot.