I created a virtual server with php-fpm and php 8.1. Later I installed php7.4 and can switch between 8.1 and 7.4 under fpm mode.
Now I want to switch to php-fcgid and I have made sure libapache2-mod-fcgid is installed
I’d personally recommend using PHP-FPM over FCGId…
The reason is, the PHP team themselves manage PHP-FPM while FCGId was more or less a project created prior to the existence of PHP-FPM to basically offer the same functionality that PHP-FPM does.
As for what you are missing, likely a package or two though it’s been a minute since I actually worked with FCGId so you might need to Google the topic if you insist on using it.
Perhaps @Joe or @Ilia might know what the missing packages are.