Comparing SAM and Terraform is like comparing apples and oranges. Comparing Terraform to CloudFormation is more appropriate, and Terraform wins in terms of verbosity there every time.

SAM generates CloudFormation templates/stacks, which create your AWS resources. Serverless generates CloudFormation templates/stacks, which create your AWS resources.

Related: I wouldn't recommend deploying raw lambda's without a framework. The development workflow really sucks without one. Use SAM or Serverless.