I want to set PubkeyAuthentication no in /etc/ssh/sshd_config, but someone should be excluded, i.e: John
PubkeyAuthentication no
/etc/ssh/sshd_config
Add something like this to your sshd_config:
sshd_config
Match User John PubkeyAuthentication yes
Don't forget to sudo systemctl reload sshd
sudo systemctl reload sshd