"We once gave you commoners this power and you used it to fuck your computer up and then blamed us for it, so we learned you can't be trusted with this power. We hid it behind a kind of skill test, and you're failing that test."
Good luck with opening the subdirectories of C:\WindowsApps\. I ran Explorer as admin, gave myself R/W permissions, even recursively changed ownership of everything, followed all the online guides... Still denied access.
Sandboxed typically restricts a program from being able to read/write to various areas (think an app isn't allowed to use the network, or access USB devices, or it's only allowed access to a certain directory in the filesystem).
Containerised is a way of virtualising an app/apps so that they can be easily distributed to run once or thousands. They can and are also sandboxed to different degrees.
I prefer the answer of giving the giy the reins and letting him get it so riddled with viruses then when he calls for support replying "sorry, your property your problem. You have absolute dominion over it and thus we give no warranty as we have no responsibility."