This screenshot perfectly illustrates just how incompatible a macOS-style app switcher is on iPadOS, where the primary user interface element is screens. In this screenshot, the current screen contains both Shortcuts and Marvis Pro, but only Shortcuts is the frontmost app so only it can be leftmost in the App Switcher. You might think Marvis Pro would (and maybe should be) second, but it’s nowhere to be found because of the other apps I had interacted with more recently.