If you get a default tiny VM (the f1 micro) with GCP, their disk IO is just a joke. 

 fio Disk Speed Tests (Mixed R/W 50/50):
 ---------------------------------
 Block Size | 4k            (IOPS) | 64k           (IOPS)
   ------   | ---            ----  | ----           ---- 
 Read       | 402.00 KB/s    (100) | 5.81 MB/s       (90)
 Write      | 423.00 KB/s    (105) | 6.14 MB/s       (95)
 Total      | 825.00 KB/s    (205) | 11.95 MB/s     (185)
            |                      |                     
 Block Size | 512k          (IOPS) | 1m            (IOPS)
   ------   | ---            ----  | ----           ---- 
 Read       | 27.45 MB/s      (53) | 36.08 MB/s      (35)
 Write      | 29.70 MB/s      (58) | 38.66 MB/s      (37)
 Total      | 57.16 MB/s     (111) | 74.75 MB/s      (72)
   
 iperf3 Network Speed Tests (IPv4):
 ---------------------------------
 Provider        | Location (Link)           | Send Speed      | Recv Speed      | Ping           
 -----           | -----                     | ----            | ----            | ----           
 Clouvider       | London, UK (10G)          | 911 Mbits/sec   | 1.29 Gbits/sec  | 94.7 ms        
 Scaleway        | Paris, FR (10G)           | 777 Mbits/sec   | 1.19 Gbits/sec  | 102 ms         
 NovoServe       | North Holland, NL (40G)   | 914 Mbits/sec   | 1.21 Gbits/sec  | 101 ms         
 Uztelecom       | Tashkent, UZ (10G)        | 760 Mbits/sec   | 606 Mbits/sec   | 191 ms         
 Clouvider       | NYC, NY, US (10G)         | 962 Mbits/sec   | 4.71 Gbits/sec  | 27.4 ms        
 Clouvider       | Dallas, TX, US (10G)      | 952 Mbits/sec   | 6.10 Gbits/sec  | 23.7 ms        
 Clouvider       | Los Angeles, CA, US (10G) | 946 Mbits/sec   | 2.69 Gbits/sec  | 47.3 ms

As you see the disk throughput is xx MB/s, though the network is pretty good.

After I changed the VM to e2 medium type, the disk IO is still worse.

 fio Disk Speed Tests (Mixed R/W 50/50):
 ---------------------------------
 Block Size | 4k            (IOPS) | 64k           (IOPS)
   ------   | ---            ----  | ----           ---- 
 Read       | 403.00 KB/s    (100) | 5.82 MB/s       (91)
 Write      | 424.00 KB/s    (106) | 6.14 MB/s       (95)
 Total      | 827.00 KB/s    (206) | 11.96 MB/s     (186)
            |                      |                     
 Block Size | 512k          (IOPS) | 1m            (IOPS)
   ------   | ---            ----  | ----           ---- 
 Read       | 27.42 MB/s      (53) | 37.69 MB/s      (36)
 Write      | 29.66 MB/s      (57) | 40.39 MB/s      (39)
 Total      | 57.09 MB/s     (110) | 78.08 MB/s      (75)

Here is my terraform configuration.

 terraform {
   required_providers {
     google = {
       source  = "hashicorp/google"
       version = "3.5.0"
     }
   }
 }
   
 provider "google" {
   credentials = file("/home/xxx/terraform/gcp/hostcache.json")
   
   project = "blissful-canyon-xxx"
   region  = "us-central1"
   zone    = "us-central1-c"
 }
   
 //resource "google_compute_network" "vpc_network" {
 //  name = "terraform-network"
 //}
   
 resource "google_compute_instance" "vm_instance" {
   name         = "terraform-instance"
   machine_type = "e2-medium"
   
   boot_disk {
     initialize_params {
       image = "debian-cloud/debian-11"
     }
   }
   
 //  scratch_disk {
 //    interface = "SCSI"
 //  }
   
   network_interface {
    network = "default"
    access_config {
       // Ephemeral public IP
    }
   }
 }

Sorry for the trial account I can't create local SSD disk in the instance. I may guess local SSD disk has better performance.