Hi @sensen_1,
How are you triggering the reset? Using Power_Ip_PerformReset() API, I can see the RESET_b line toggling every 2.7ms, which matches with the Data Sheet's value for boot time with no HSE FW installed:

Of course, full startup and peripheral initialization also add to the boot time.
If you have HSE firmware installed, S32K3 adds SBAF and Firmware initialization upon booting. This is described in 6.1.3 Boot time, HSE firmware installed.
Best regards,
Julián