[xrisk]

Did switching your deliverer to SES have any effect on how clients like Gmail “tagged” your email? (Promotional category or something IIRC)

[tsukikage]

Nope. The biggest impact on gmail was making sure I had DMARC, DKIM and SPF all set up correctly.

(I tried several other relay services like mailgun and those /did/ have noticeable impact - SES was the first one I tried that didn't, so I stuck with it).