I've really tried to like the new Outlook, but it just plain sucks. I certainly don't need many of the features in classic Outlook, but some of the simpler ones are important to me.
Example 1: I have several email accounts. When I get a message in account A, I sometimes want to use a reply from account B to steer the rest of the conversation to that account. Can't do it in new Outlook.
Example 2: When cleaning up one of my inboxes, I search on the from field and then reorder on that field. If I do that in new Outlook, it only shows the sender I searched on. This is a very inefficient way to clean up my inbox. Classic Outlook still displays all my messages, with the slightly different names nearby.
Classic Outlook does a much better job of organizing things, even for basic usage. And it still baffles me that an app with a small subset of features takes three times the amount of memory than the fully featured version. Why would anyone triple the code footprint to remove features? I've spent some six decades as a software engineering professional, and I can't imagine such a thing.