I am currently using the RTD version SW32K3_RTD_4.4_R21-11_3.0.0_P01 for S32K3x4, but I am unable to locate the RAMTST and FLSTST modules—do I need to download an additional MCAL or safety package to access them?
No, these modules are not part of the standard RTD package.
This functionality is a part of the S32 Safety Software Framework (SAF), which is a premium safety package offered by NXP:
https://www.nxp.com/design/design-center/software/functional-safety-software/s32-safety-software-fra...