First your php or apache has been misconfigured not this was done on Ubuntu 22.04 LTS
First uninstall all php versions
sudo apt purge php*
then install the lattest and other packages
sudo apt install php8.0-common php8.0-cli
sudo apt install php8.0
sudo apt install php
Check if it was installed successfully and version installed
php -v
Then restart apache2
sudo systemctl restart apache2
Then install other packages
sudo apt install php8.0 libapache2-mod-php8.0
sudo apt install php8.0-fpm libapache2-mod-fcgid
sudo a2enmod proxy_fcgi setenvif
sudo a2enconf php8.0-fpm
systemctl restart apache2
sudo apt install php-xml
sudo apt install php-mysqli
FINALLY RESTART apache2 and enjoy
systemctl restart apache2
I HOPE THIS SOLVES YOUR PROBLEM