Not to sound like a dick, but if you take a little bit of time to learn how multitasking on iPadOS 15 works, you’d learn how to avoid creating these additional windows to begin with. Mashing away with your fingers and taping/dragging in random directions is likely what is creating them in the first place. The truth is that these minimized windows add a lot of power to iPadOS that isn’t quite to easy to see on the surface.
But they are correct that since Apple had a switch to disable multitasking before, it really should still be possible to disable it. This is just Apple's loathing of giving users the ability to configure/customize the OS. I can imagine a lot of iPad users would prefer a simpler system similar to an iPhone.
Not to sound like a whiner, but my age and infirmities do lead to just the problems you describe, "Mashing away with your fingers and taping/dragging in random directions is likely what is creating them in the first place." I'm not into the the far reaches of the iPad's capabilities, just the normal email, Internet, FaceTime now and then. Seems to me that a front-running company like Apple would have kept a switch that let me fumble along my merry way while you explore the vast reaches, etc.
You can leave draft emails open and unsaved on the iPhone as well; they're down at the bottom of the screen.
I can only see a single draft email at a time and it only seems to display when using iCloud but not my normal email provider. I've never noticed it before. Hardly the same thing though. It is much simpler.
Here there are five unsaved draft emails from a regular IMAP account at the bottom of the screen. When you tap on them they expand and you either swipe or tap the X to close them. On the phone you don't know how many drafts/windows are open unless you tap the bottom, and you always see them at the bottom; the iPad shows you how many are open when you switch to it and then they are hidden from view. Subjective difference, but I prefer the iPad's method.
I see that now. Seems buggy. I was getting very different results earlier. Sometimes the "New Message" disappeared even when there were multiple drafts. Other times, it would just show the last draft when tapped and not the multiple draft screen.
To be fair, closing and saving a draft email on my Mac acts differently from minimizing a draft email to the dock
