But the problem is that Mailgun/Sendgrid/Postmark and the like is less senstive to spam and ban. The ban on SES is way heavier and the spam rule is stricer.
Maigun/Sendgrid even suggest to use dedicated IP pool to improve delivery, where as AWS SES doesn't https://docs.aws.amazon.com/ses/latest/dg/dedicated-ip.html https://docs.sendgrid.com/ui/account-and-settings/dedicated-... You can see the tone there.