There are many people posting about many variations of email issues since 18.1. For me:
I have had email since 1986. I have my own email on a shared server as well as other email accounts I have used for YEARS including Gmail. I have used an iPhone since a month after first release....
IOS 18 Apple Mail removed the ability to PUSH email accounts other than iCloud, Yahoo and one I forgot. Gmail is NOT one of them. Nor any of MY other emails.
Forever and until last week, I could send my self an email and watch the Mail badge update within 2 minutes if not MUCH sooner. Now, Gmail for example (so we don't start blaming my other email accounts and servers) are FETCH only. There is no drop down option for PUSH any longer for it. And even if PUSH is globally selected, it will only fetch unless iCLoud, Yahoo and that one other. The quickest update interval for FETCH is 15 minutes.
Now Fetch will try every 15 minutes. If you receive an email and it is close to that 15 minute fetch, it might appear push is working. But if fetch had just run, it could be 15 minutes until the badge changes and a notification for the email appears. And I, as others, can often get double the number of emails on the badge than are really there.
This is...
So, unless I have missed something and I doubt I have, Apple quietly emasculated Apple Mail.
The reason some can get mail under power plugged in AND on WiFi, is that fetch works automatically ONLY in that scenario.
MY gut, unfortunately says Apple is not going to fix this one. They likely think they are saving battery power. They will likely claim no other email supports push.
I'd love to know what others hear and if there is a great third party email app for multple IMAP accounts with push and other rich features.