i have no clue wtf its saying since i dont have forge multipart i just want to use NEI and i cant even do that

The game crashed whilst there was a severe problem during mod loading that has caused the game to fail
Error: cpw.mods.fml.common.LoaderException: java.lang.NoClassDefFoundError: codechicken/multipart/JItemMultiPart
Exit Code: -1

Unfortunately, any version other than those found on Minecraft 1.16 is not supported.

Additionally, for future issue reports, please be sure to attach your full crash report (found in the crash-reports folder, next to your mods folder), as the snippet you have provided, literally tells me nothing.