MySQL 8.0 service won't start "directory exists"
This solved the problem:
# Allow directory changes in AppArmor
sudo sed -i '/\# Allow data files dir access/a /mysql/** rwk,' /etc/apparmor.d/usr.sbin.mysqld
sudo systemctl stop apparmor.service
sleep 10
sudo systemctl start apparmor.service
removed the lost+found folders from the /mysql/ subfolders and initialized the db using
sudo -u mysql mysqld --initialize