Why is it that when I start up Teams it automatically opens up my Chats first?

Yes! Classic Teams provided the functionality I need from this product for my work, which is the calendar. I have no need to view the chats, except when I'm in a meeting (and I can see them there) or if there is an attachment or recording that I need later (and then I go to the chats and get them). For my productivity, I need the calendar.

Classic Teams would open on the last app that was active once opened again. This is a very important feature for many of us and it's not clear why it's gone.

Mac and Windows user. It ALWAYS opens in Chat on both. I just want to switch it to my preference, which is Teams. You'd think for an application called Teams that they would default to that tab. Anyway, I don't understand the Microsoft response at all. I don't click on my photo to open settings, I use the three dots on both platforms. And neither platform has the application section that was mentioned. I feel gaslit at every step.

Oh look, another MS product where they chose to go with randomness over practical functionality.

Windows user, Teams starts in Teams, I want it to start in Chat. Dragging Chat to the top, or unpinning and repinning it has no effect.

Uncheck the box that says "Register the new teams as the chat app for Microsoft 365 (requires restarting Microsoft 365 applications)"

This seems to have worked for me, it no longer opens to the "Chat" screen by default.

Mine is currently unchecked and opens to chat every time.

Do you restart your computer or just put it to sleep? If I close the app and re-open it'll open again to wherever I left it, but if I shut down / restart then it will re-open to chat every time.