How to calculate the account return rate

There are multiple methods to calculate the return on a securities account, such as the simple return method and the compound return method. Considering that the account funds are subject to inflows and outflows, how can the return during the period be objectively reflected and avoid distortion? I use the net asset value (NAV) method, treating the account as a fund, with fund inflows and outflows regarded as subscriptions and redemptions (the so-called NAV method return, which can also be called time-weighted return, a method used by all funds).
My account had 16 inflows and outflows between 2019 and 2025 (some data hidden due to size limitations). By calculating the monthly return using the NAV method, I can plot the account’s monthly net value changes alongside the Shanghai Composite Index trend (setting the initial funds and the Shanghai Index closing price in 2018 as 1). Over seven years, the account’s net value increased from 1 to 2.173, with an annualized return of 16.76%.