Why is the macOS app's UI/UX so terrible?

I mean, what’s going with the “Switch model“ selector?

This is what it looked like a couple of updates ago:

After that an unnecessary submenu was added:

And now we have that:

Seriously? What’s next?

And why don’t the links open?

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What’s going on with the “New chat“ button? Why does this button move to the right after closing the sidebar?

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