I’ve been running my own email server for years, and while it’s indeed difficult at first, it is possible and you don’t have much to do to maintain it when it works. All the horror stories you hear come from the fact it’s difficult to get right, and even when you get it right, you will have deliverability problems the first year, until your domain name gets established (and provided you don’t use it for spam, obviously - and yes, marketing is spam).

What you need :

• being willing and serious about reading lot of documentation
• an IP that is not recognized as a home IP. So you’ll need a “business ISP”, or one that is not well known. You bypass this problem by using AWS.
• choosing a well recognized TLD for your domain name, like .com, .org, .net, etc. Don’t use one of those fancy new extensions (.shop, .biz, etc), they are associated with spammers.
• learning how SPF works and getting it right (there are plenty of documentation and test tools for that)
• same for DKIM
• same for DMARC

Start using that for a year without making it your main address. Best is to use it for things not too mainstream, like FOSS mailing lists, discussing with people having their own mailserver, etc, those will not drop your mails randomly. When a year has gone with frequent usage, you can migrate to that email address or domain.

Regarding the architecture of your network : do you read your emails on several machines (like, on mobile and laptop)? If not, you can dramatically simplify your design by using pop3 instead of imap, connecting your client to the AWS server, downloading all your emails to computer and removing them from the server at the same time. There, you have all your mails locally and you don’t need dovecot. :)