That's fair. I still think the model is much worse on iPadOS ... in many cases outright broken and not just unintuitive, as I pointed out with messages/safari.
I don't really have the same problem with focus windows as you on macOS ... it's generally pretty clear (used to be even more clear) and when I lose track of focus it tends to be because I have many monitors and there's a lot to keep track of.
Yes and this is exactly why macOS should be on the iPad. Not replacing iPadOS, but as an adjunct. We have 40 years of UI iteration on macOS for window based multitasking and full operating system goodness. Meanwhile, iPadOS has its roots in a single app at a time mobile model and this split screen mode they've implemented has basically failed to evolve in the past few years. This indicates to me they have no idea where to take the model, possibly because there isn't actually anywhere to take it. I don't need or want touch-based versions of Xcode/Final Cut Pro/Photoshop, etc.
It doesn’t need to be MacOS (in fact, it shouldn’t be macos - no need to abandon the good things in iPadOS), but a more macos-like windowing interface would go a long way.