Try using the bash shell (by typing "bash" in the terminal window) and setup the environment with that instead of zsh.

mymac[~] bash

The default interactive shell is now zsh.

To update your account to use zsh, please run `chsh -s /bin/zsh`.

For more details, please visit https://support.apple.com/kb/HT208050.

bash-3.2$ export FREESURFER_HOME=/Applications/freesurfer/8..0.0

bash-3.2$ source /Applications/freesurfer/8.0.0/SetUpFreeSurfer.sh

-------- freesurfer-macOS-darwin_x86_64-8.0.0-20250205-0f2bd3a --------

Setting up environment for FreeSurfer/FS-FAST (and FSL)

FREESURFER_HOME   /Applications/freesurfer/8.0.0

FSFAST_HOME       /Applications/freesurfer/8.0.0/fsfast

FSF_OUTPUT_FORMAT nii.gz

SUBJECTS_DIR      /Applications/freesurfer/8.0.0/subjects

MNI_DIR           /Applications/freesurfer/8.0.0/mni

if the above works you could try changing your default shell to bash with "chsh -s /bin/bash"

- R.