Sendgrid emails ending in spam - sendgrid

Can someone point me to good article about what I can do to prevent my sendgrid emails from ending in spam? I’m using gmail.
I implemented an email drip campaign that ends up in the promotions folder or spam.

Related

GMail - Email Sent To Multiple People (CC'd) Received At Different Times

Our organization sends an email to all of our employees several times a month. Sometimes, we'll have accounting send time-sensitive emails to particular contacts, but all CC'd. Why would someone who is also on gsuite, but a different gsuite account, receive the email at 12:00PM and someone else might receive it at 5:00PM? All users either on the same organizational gsuite account, or another organizational gsuite account.

Mail Landing in Gmail Spam folder

After updating DKIM DMARC and SPF email is still landing in Gmail SPAM folder.
In the email header, it is showing DKIM DMARC and SPF Pass and domain and IP address not black listed in https://postmaster.google.com/
Please let us know is there any changes has done in the Google Mail policy.
Is there any other steps we need to follow to receive the emails in Gmail Inbox.

Adding custom "from" email in Amazon SES similar to sendgrid

I have been using Sendgrid for sometime, and I like the service but after 100,000 emails quota the pricing jumps. I was looking at AWS SES service, but was unclear if "from" email address can be custom set without verification similar to sendgrid. My app users send emails to their personal contact list from my app so I want their contacts to see my users personal email in the "from" email when their contact reads the mail.
Or Does all my users have to verify their email address through Amazon even though My app has already verified their email address at App account Signup.
Your app users cannot use their personal email as a MAIL FROM unless it's verified in SES (either the specific email address or its domain).
The MAIL FROM domain must be a subdomain of the verified identity
(email address or domain) from which you will send your emails.
See Using a Custom MAIL FROM Domain with Amazon SES for more details.

Mailchimp - send newsletter approve email

One of our customers had a campaign and forgot to add "newsletter approve" field on it, he asked us to send an email to the whole list of leads from the campaign to approve newsletter, in case user approved the newsletter from the email he should be added to the newsletter list automatically.
does anyone know how (if) it is possible, i can't find anything about that in mailchimp.
appreciate any help, cheers! :)

How to implement Email Anonymization Similar to Craigslist

I am developing a site for which I would like to protect buyers by anonymizing their email addresses.Similar to craigslist's system, when a seller needs to contact a buyer they should be able to send an email to an anonymized address such as 142jijisds#mysite.com which will then be routed to the user's email address.
But I don't know how to implement this feature.