You can "suspend" user apps via
cmd package suspend <packageName> (which acts kind of like
pm disable; the differences are explained in this answer by @Firelord), and later unsuspend them using
cmd package unsuspend <packageName> – which also works for user-installed apps. However: suspended packages seem no longer to be listed via
cmd package list packages – not even if
-u (uninstalled) or
-d (disabled) is specified; not even
dumpsys package seems to know them anymore.
So is there any way to obtain a list of suspended packages? The syntax output doesn't mention such. But as such apps are still shown in the launcher (though "grayed out"), there must be a way to detect them.