Mail. New mailbox layout is really annoying. Can I change it back?

I am using Mail on OS11.6 (I can't update any more until Adobe updates a couple of apps to match MacOS). Recently Mail reorganised the lefthand mailbox column. It used to be that I had all inboxes at the top then Sent and then other automatic folders etc If I selected "All inboxes" I saw all incoming mail.

Now the lefthand column is listed by account, each one having its own inbox, sent, trash etc. It's really counter intuitive and cumbersome to work with. Checking the mail now involves rooting around to look at each individual inbox. Can I change it back? Did I inadvertently change this or does Apple now think this is the way forward?