I am using the AWS Ubuntu server(PHP 7.2 installed) for Magento 2.3.5 -p1 version, It is very fast in most cases(page loading, registration, login) but when sending email via SMTP it is taking too long to send the email. Why this is happening I have also changed email service provider (Gmail, Sendgrid, etc.) and updated all available configuration to send emails in Magento Admin like(asynchronous sending enabled, etc.) but no improvement is seen. What should I do to send an email fastly?