The problem with Outlook is that Microsoft makes more money shoving ads in your face with the inferior version than they do selling the better product. They track what you're browsing in Edge and show you ads relevant to what you're browsing for in the new ad-laden Outlook.
I was going to switch to Thunderbird anyway, I want to use as little Microsoft software as possible, but I'm going to take the extra step of ditching their email service. They even put ads in the webmail version of Outlook, and lately they have been sending email from sources that they themselves mark as trusted senders to the Junk folder, including my bank!
I'm beginning to think that Microsoft is shooting itself in the foot with all these Windows shenanigans. Linux is a viable alternative to Windows for the average PC user, and it just needs a catalyst to get people using it.