Does the following command not use swiftmailer normal email sending?

php bin/console swiftmailer:email:send

When using this with my configuration everything works using AWS SES so it doesn't make sense that I'd need to do anything special unless i need to reformat like 464 as you describe. I'll try to determine how to do that. The reference link you sent is fairly vague and I'm not a php developer so I'll play with this a bit more but so far (I'm guessing I just need to fix which fields are passed such as the sender), I keep getting failures when I clear cache so I'm concerned I'm breaking other things.