what will cause RCM_SRS_SW_MASK （software） reset？
This is a software reset.
Which registers can be cleared manually for non power-on reset so that they are the same as power-on reset status
There is no list of registers that are cleared on POR only.
Each registers has its own specification.
Some registers are reset only on power-on reset.
Could you read the RCM_SRS during startup to find the source of the reset?
RCM_SRS_PIN_MASK this reason again and again
If you see RCR_PIN = 1, that means that another device connected to the reset_b pin is the cause of the reset, not the MCU itself.