Is it possible to send emails via AWS SES on AWS LightSail instance?

I have tried sending emails on my LightSail instance via AWS SES using the following Node.js JavaScript AWS SDK code, but it failed with the following error message. The email sending code works fine on my development computer. (The email sending code is from https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/ses-examples-sending-email.html.)

(code here)

import { readFile } from 'fs/promises';
import * as path from 'path';
import { SESClient } from "@aws-sdk/client-ses";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const awsConfigFileFullName = "aws_config.json";

let awsConfigFileFullPath = path.join(__dirname, awsConfigFileFullName);

const awsConfig = await readFile(awsConfigFileFullPath).then(json => JSON.parse(json)).catch(() => null);

aws_ses_client = new SESClient({ region: awsConfig.region, accessKeyId: awsConfig.accessKeyId, secretAccessKey: awsConfig.secretAccessKey });

const createSendEmailCommand = (toAddress, fromAddress, htmlContent, textContent, emailSubject) => {
  return new SendEmailCommand({
	Destination: {
	  /* required */
	  CcAddresses: [
		/* more items */
	  ],
	  ToAddresses: [
		toAddress,
		/* more To-email addresses */
	  ],
	},
	Message: {
	  /* required */
	  Body: {
		/* required */
		Html: {
		  Charset: "UTF-8",
		  Data: htmlContent,
		},
		Text: {
		  Charset: "UTF-8",
		  Data: textContent,
		},
	  },
	  Subject: {
		Charset: "UTF-8",
		Data: emailSubject,
	  },
	},
	Source: emailSenderName + '<' + fromAddress + '>',
	ReplyToAddresses: [
	  /* more items */
	],
  });
};

const sendEmailCommand = createSendEmailCommand(
recipientEmailAddress,
senderEmailAddress,
htmlEmailContent,
textEmailContent,
emailSubject
);

try {
await aws_ses_client.send(sendEmailCommand);
} catch (e) {
console.error("Failed to send email.", e);
}

(error here)

AccessDenied: User arn:aws:sts::(some number):assumed-role/AmazonLightsailInstanceRole/i-(some alphanumeric number)is not authorized to perform ses:SendEmail' on resource `arn:aws:ses:us-east-1:(some number):identity/(recipient email address)'

After doing some search online on the issue, thinking that the error was caused by port 25 restriction on Lightsail instance restriction (https://aws.amazon.com/premiumsupport/knowledge-center/lightsail-port-25-throttle/), I sent a restriction removal request to AWS, but the request was declined, telling me to "consider looking into the Simple Email Service". I sent a reply asking if sending emails via AWS SES was possible on LightSail instance, but got a reply saying "we cannot grant your request"; I feel that the second reply was either automated or wasn't even thoroughly read by the person who reviewed the email.

I have a multisite WordPress installed on my LightSail webserver, which can send emails via AWS SES with WP Mail SMTP plugin, with TLS encryption using SMTP port 587. I think this is a proof that emails can be sent on a LightSail instance via AWS SES. Emails do get sent by my WordPress on my LightSail webserver, everyday, using my AWS SES SMTP credentials; so, maybe the AWS SES SMTP server must be directly contacted in the LightSail instance email sending code to send emails, instead of using the authenticated SES client object in the code?

I'm thinking that maybe the assumed role AmazonLightsailInstanceRole doesn't have AWS SES email sending allowed. I've checked my AWS IAM web console, and there was no role named AmazonLightsailInstanceRole; it doesn't look like I can modify the policy on the assumed role AmazonLightsailInstanceRole.

Can AWS SES email-sending permission be granted to the assumed role AmazonLightsailInstanceRole? If so, how?

Is it possible to send emails via AWS SES on an AWS LightSail instance? If so, how can it be done in Node.js JavaScript AWS SDK code? Any verifications, references and/or directions would be very helpful.