Both will do. Fund diversification can be used to make a fund portfolio and allocate different types of funds. This method can spread the investment risk, and the management is relatively complicated, which is more suitable for the steady investors.

When you are firmly optimistic about the market or fund, you can concentrate on buying at one time and get excess returns. This method is risky and not too complicated to manage, and it is more suitable for investors who are most interested in returns.