You inherited an account with 300 resources created by hand over three years, and you were asked to "put it in Terraform". You have two paths: generate the code automatically from the infrastructure that already exists (import, reverse-engineering tools), or sit down and write it by hand. The easy answer is "generate it, obviously". The right answer is "it depends what you are trying to achieve".

What generated Terraform gives you

Generating the code has one enormous virtue: speed and fidelity. Instead of guessing the exact configuration of 300 resources, a tool reads them from the cloud and emits HCL describing them exactly as they are.…