The first rule of UX design, as far as I'm concerned, is: Don't make me think.

Moving stuff around? You just made me think. You'd better have a good reason for that, better than just "it will play better on touch devices". I'm not on a touch device, so you just slowed me down to solve a problem that I don't have.

I agree. Teams is pretty bad about this. Every few weeks some buttons get moved around so you have to look for them. Instead of fixing problems it seems they just keep changing the UI.

Why does MacOS do it?

Because they don't have start button and corners are used to trigger actions (hot corners).

But macOS does it differently, visually it looks far pleasing that what is shown here.

I’m not a huge fan of macOS dock bar but UX wise it isn’t so bad.

You can move it back to the corner in the settings.

But why the change at all? I wonder what their user story for this one was.

I have wondered that too, I don't like the look of the new taskbar, I was hoping they'd do more with it with some of the user concepts floating around (such as a rounded floating taskbar.) I'm sure the true reason is that is what MacOS does, so they just copied it.

With (ultra)widescreens these days moving the Start Menu and Search boxes to the center of the screen makes a lot of sense. Literally brings them "front and center", and I guess if the menus/windows/boxes are moving to the center, moving the icons that open them to the center makes sense.

As a vertical taskbar user (since way back in XP days) though, I'm definitely upset by all the wasted space. I'm perplexed why they aren't allowing vertical taskbars at launch. I'm sure telemetry suggests most users keep a bottom taskbar.