500 error on phpmyadmin link

You need to install said php modules [TUTORIAL] How to install any PHP modules using PEAR Package Manager

php 7.4 has always been a safe bet for running an error free cyberpanel

You need to change permissions for /usr/local/CyberCP/public/phpmyadmin such as

$ chmod -R 777 /usr/local/CyberCP/public/phpmyadmin/tmp