Most of my issues with this on the Mac seem to be SwiftUI related. For example, the passwords panel in the new settings app scrolls at roughly 15 fps and the notification center opening gesture (two fingers from right edge to left) is about the same. See also the Font Book app before and after they rewrote it (either Monterey or Ventura, I think). Most of the older features and animations are smoother.

Absolutely. I wonder how much it's planned obsolescence, but my iPhone XS has been feeling extremely flaky lately. Many seconds long lock-ups resulting in crashes of both apps when opening an app while on a call, for example.

I understand their goal of pushing you to buy a new device, but this doesn't really do that. It makes me hesitant to buy a new one in case it will also perform this badly. There's nothing inherent to the hardware that should make it perform this badly and I don't think that it did that when it was new. Ergo I think their software has taken a nose dive into extreme unreliability.

Yeah that. I just started using Windows again recently and macOS feels sluggish and clunky in comparison.

Not on the 15 pro. It uses the 3nm processor to get the snappiness back. Even my 13 pro was losing the snappiness. Crazy stuff.