How to testiampermissions with sufficient access token?

I am trying to use the GAPI to read a spreadsheet (through frontend JS) and am trying to make it so the permissions window doesn’t come up everytime the user logs in. To do this I am trying to use TestIamPermissions(), but it reponds with a 403 PERMISSION_DENIED with the reason ACCESS_TOKEN_SCOPE_INSUFFICIENT. From what I found on the web, I have to use something like https://www.googleapis.com/auth/cloudfunctions as a scope. I have done this and have authorized it on the google account, but it still returns an error.

This is the code relating to the request:

gapi.client.request({
    path: `https://cloudresourcemanager.googleapis.com/v1/projects/gamblingdatabase-455413:testIamPermissions`,
    headers: {"Authorization": "Bearer "+ACCESS_TOKEN},
    method: 'POST',
    body: {
        permissions: ["drive.files.get", "drive.files.update"]
    }
}).then(response => {
    if(response.result.permissions && response.result.permissions.includes("drive.files.get") && response.result.permissions.includes("drive.files.update")){
        SCOPES = "";
    }
});

And this is what the error repsonse is:

{
  "error": {
    "code": 403,
    "message": "Request had insufficient authentication scopes.",
    "status": "PERMISSION_DENIED",
    "details": [
      {
        "@type": "type.googleapis.com/google.rpc.ErrorInfo",
        "reason": "ACCESS_TOKEN_SCOPE_INSUFFICIENT",
        "metadata": {
          "method": "google.cloudresourcemanager.v1.Projects.TestIamPermissions",
          "service": "cloudresourcemanager.googleapis.com"
        }
      }
    ]
  }
}

All varaibles are correctly initialized and in scope. I’m very new to the Google API and networking in general and am not sure what to do.