push notifications from sub folders in mail no longer alert

Since upgrading to iOS 13.4, I no longer receive audio alerts when new mail comes into a sub folder of my inbox. This has happened before, but it was usually a bug in the iOS which was rectified.

I SERIOUSLY need to be able to get audio notifications of Inbox sub folders in Mail.

I'm on call all the time and I have set up sub folders to help me manage the e-mail. It will indicate new messages, but I only HEAR the mail sound on the Inbox. I therefore have to constantly check my phone, which is unreasonable when I used to be able to know there was new mail just by hearing the audio cue that told me to check it.

I'm using Office 365 and have been for 5 years over 2 different iPhones and this is by far one of the most important features on my phone. No, Outlook or Office 365 is not an option. It does not allow me to see sub folders and does not pull in the mail in a timely fashion. It will literally be 2 days before I see anything new in my inbox. Adding subfolders as favorite folders, as some have suggested, also doesn't work well. I have over 100 sub folders I would have to add.

Thing is, this used to work BEAUTIFULLY. It was one of the better parts of having an iPhone. I have been told this was part of the upgrade. It needs to come back. Third party applications don't work well with new messages, alerting on new messages, showing folders... all the things that Mail used to do. Please someone fix this issue.