TTY`s are beeing started if theres file in /etc/init/tty[1-6].conf and it contains line start on runlevel [23] Long method is to make line unexecutable by puting in front of it # #start on runlevel [23]
Faster is just Remove 4 virtual TTY terminals using in terminal removing command for desired TTY terminals
sudo rm /etc/init/tty3.conf && \ sudo rm /etc/init/tty4.conf && \ sudo rm /etc/init/tty5.conf && \ sudo rm /etc/init/tty6.conf