I’ll add another one to the list of monitoring.

Add an alert of sent email threshold. I log to gray log, and if more than 5 are sent in 5 minutes it will send me an alert.

I do. But the domain I use it for is occasional sending. If it was for my job/business probably not.

I do not notice any delivery problems though. What you will need aside from DKIM/SPF, is a static IP and the ability to create reverse dns records.

I have Comcast business and I was surprised they did the reverse dns for me, but it has been working great. I get 10/10 on mail-tester.com.