Virtualmin supports multiple PHP versions per virtual server. On AlmaLinux/Rocky Linux/CentOS/Oracle Linux/Fedora Linux, you can enable Remi's Repo and install PHP from there.

. /etc/os-release && dnf -y install https://rpms.remirepo.net/enterprise/remi-release-$(rpm -E %$ID).rpm && dnf clean all

Install additional PHP packages like normal.

dnf install php*-php-{cli,fpm,pdo,gd,mbstring,mysqlnd,opcache,xml,zip}

For example, to install PHP 8.2, run the command as:

dnf install php82-php-{cli,fpm,pdo,gd,mbstring,mysqlnd,opcache,xml,zip}

In Virtualmin, go to your virtual server > Server Configuration > PHP Options and then select the PHP version.