snoodler
Ah okay, Apache2. Did you install+configure php7.3-fpm manually? Since on default install Apache2 uses its default internal PHP handler (mod-php), hence php7.3-fpm is not required.
So you could clean up things and assure the Apache2 PHP module being active:
apt install libapache2-mod-php7.3
apt purge php7.3-fpm
a2enmod mpm_prefork php7.3
systemctl restart apache2