This setup allows restrictive chmods, which prevents users for reading the conents of each others directories and provides a layer of security against reading raw PHP code in case of FPM failure. You can set chmod 600 for all .php files and chmod 640/710 for any other static files/dirs.
certbot certonly -d example.com
useradd -m -d /home/example -s /bin/bash example
usermod -a -G nginx example
su - example -c "mkdir ~/www"
chmod 710 /home/example
chmod 710 /home/example/www
su - example -c "echo '' > ~/www/index.php"