This Six Colors post on iOS 18.2 mail is spot on - sixcolors.com/post/2024/12/ios

I'd rate Mobile Mail on iOS as a dumpster fire and I'm quickly considering replacing the Mail icon with Outlook. That's how bad it's gotten.

I disabled categories and the AI features but search is continually broken pushing me to "connect to wifi and a charger to search your mail" When I click a new mail notification, it takes 10 seconds for the message to load.