I need to perform FME server (2022) silent installation in EC2 machine, do I need to create response file or there is any script that we can directly execute using cmd.

https://docs.safe.com/fme/html/FME_Server_Documentation/AdminGuide/Silent-Install-Windows.htm should help you on your way.

You'll have to configure the load balancer separately, if its an AWS load balance you'll more than likely be able to do this programmatically using the api.

Re the database, you'll have to script the following documentation:

https://docs.safe.com/fme/html/FME_Server_Documentation/AdminGuide/Provide_Database_Server-2-Tier.htm

Here is an example of a script i've used previously. Note, only use at as a guide, this is more a framework than anything else

https://github.com/thewabbit/fmeserverinstall

This is great Hamish, thanks a tonne for sharing this - excellent starting point