Mail app still isn’t to iOS12 levels. It is better than 13.2 but still not right.
When a notification shows up and I open the mail app, most of the time it will appear almost instantly. However a couple times now, I have to wait a second or so for it. This is better than waiting the 5 seconds on 13.2
However, in iOS 12, if it notified you of an email, when you opened the app, it would ALREADY be there in the list, 100% of the time. In iOS 13.3 it is still waiting til you open the app to actually load the email into the list. This needs to get fixed.