It looks like only ADFLIB support FFT. However, ADFLIB is for S32Z/E/V. S32K3xx_AMMCLIB_v1.1.41 I downloaded does not have ADFLIB. Could you sent me a ADFLIB suitable for S32K3? Thanks.
You are right, for S32K3xx, CMSIS DSP is the optimal option.
AMMCLib does not currently provide FFT for the K3 device and there is no immediate plan to add it. The main reason is that this functionality is already available in the CMSIS-DSP standard library. CMSIS-DSP is provided by compiler vendors, e.g.: