The price of open-end funds is calculated by the weighted average rise and fall of the stocks held, but a certain fund management fee is charged. If there is no free labor, the foundation will help you buy stocks and charge you a certain fee. That's it.
Net worth has little effect on income, only on dividends, because dividends are paid according to the fund share, but your total income is the same.
PS: Most funds belong to stock type. Fund investment itself is to buy stocks with money, so its rise and fall depends on stocks. Good fund companies have good fund managers. If the stock it buys is better, it will go up. If they buy, they usually go up. If they don't buy well, they will fall.
So the quality of the stock market is related to the trend of the fund.