Gmail not using All Mail folder on Apple Mail

Mail maps All Mail label to Archive.

If the Archive contains deleted messages, take a look at the Mailbox Behaviors for the account and see if Trash is set to Archive.

I don't use an archive at all. I move most everything to Trash. If I want to keep it for posterity, I move it to a folder either On My Mac if I will never need it on another device, or I move it to a folder in iCloud if I need to access it from some other place.

Gmail created All Mail to make sure they have access to everything you have ever sent or received. Since it is somewhat an Archive, Apple chose to map the All Mail label to the Archive folder. Gmail can assign multiple labels to a message. All incoming messages have at least two labels, Inbox and All Mail. Deleting from the Inbox translates to "Remove Inbox Label from message and add Deleted Message Label," not move message to Trash or delete message.

What you do with your discarded messages depends on how you want to work.

Using Gmail in an IMAP-compliant email client is mostly a test of wills. It is best used on the Gmail web portal.

It was / is indeed mapped to Archive, is this correct. ?

That’s what Mail does.

but also there is no longer any mail in my All Mail folder on gmails web app, so wondering what has shifted. It worked perfectly for years

I don’t know why that would happen.

Makes sense

still not sure how or why I’ve lost “all mail” label on my entire account in gmail.

I wonder about that, too. Seems like that is something Gmail would prevent you from deleting. You can delete the contents, but if the Label is gone, I don't know how that is possible.

You can hide labels. Mine is buried under the More section.