Mail folders not showing on iphone

I have an iPhone SE running iOS 18.3. Recently the

contents of my mail folders have shown “no mail” and in the last 48 hours or so

the folders disappeared altogether. And then since starting to type this all

the folders have suddenly reappeared in “All Mail” but still with “no mail” showing

in all the folders. I now also have 1058 unread emails which is complete

nonsense as I cleared my unread mails a few days ago! The folders always used

to be visible in All Archive but they haven’t reappeared there!

Up until now my Gmail account has synched seamlessly

using new Outlook (and the earlier version) on a Windows 10 PC and Mail on my iPhone.

My Gmail still works fine on Outlook and the folders and

their contents can be edited and synch with my Gmail account. The folders match

the labels in Gmail. I can still receive and send emails on Mail but the

folders were until a few minutes ago missing from All mail.

I have deleted and reinstalled my Gmail account on Mail,

I have tried changing the GMAIL IMAP Path Prefix from blank to INBOX and back

again but that doesn’t make any difference.

Help or do I just abandon Mail and switch to Outlook on

my phone!