You can kind of do this already, but only via split screen multi tasking.The only thing that I love about macOS that can’t really be accomplished on iPadOS is the multiple desktops. I never really see anyone talk about this, but I love being able to have multiple different safari browsers open with different themed tabs and a bunch of different google docs and things of that nature. This level of multitasking just doesnt work for me on my iPad Pro. I’m a teacher and we use Google Apps so I always have a ton of Docs, sheets, and slides open. I use the pencil all the time and airplay my iPad to the board and move about the room freely, so when I’m teaching the iPad is a very powerful tool, but when it comes to managing documents I’m always on my MacBook. I think I could get by with just my iPad, but it would be less convenient and more time consuming.
I say all that to say this, if my iPad could dual boot macOS when attached to the smart keyboard, it would be the holy grail machine for me. Unfortunately I don’t think we will see this. My guess is iPadOS 15 will just be able to run some Mac apps that other professionals use.
But you can have any number of Safari windows, notes, and other apps with multiple instances open, side by side, then four finger swip to flick between them