Which version of the provider are you using? The documentation reference you provided is for data sources rather than resources, so this would be a better reference: https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticache_global_replication_group#engine-1.

resource "aws_elasticache_replication_group" "primary" {
  replication_group_id = "example-primary"
  description          = "primary replication group"

  engine         = "valkey"
  engine_version = "7.0" # or whichever version you need
  node_type      = "cache.m5.large"

  num_cache_clusters = 1
}