I have been having an issue with Mail on my iPad Pro of late. For some reason the mail app was having issues loading. I would open it and it would be empty and blank, and take up to a minute to load if it loaded without crashing. This also meant I was unable to send e-mail from other apps unless, I first got Mail itself to load. And this only started recently.
I had tried turning off all my mail except my Apple mail account, and even tried resetting network settings, but mail was not working correctly for the last couple of weeks, and it was driving me nuts. I was about to backup and wipe the ipad, but was waiting for the update to see if it fixed it.
Yesterday apple released iPad OS 15.6 and after updating the Mail issue has been solved, if only that was the only issue that recently cropped up on my iPad.
At the same time as the mail issue, Safari has started losing logins for web sites. Sites that for years have stayed logged in, must be logged in every time that I got to the site. So every time I use bing or google I need to log in again. Super frustrating, and unfortunately not fixed by 15.6.