1. snapping. There is not a built in key for this, you’re right. However you can double click on the edge of a window to make it size to the edge of the screen. Additionally you can set the double click of the title bar to scale the window (which usually is to the top and bottom of the screen.

HOWEVER: this can be accomplished using an AppleScript which can be bound to a keyboard command. Yes… it’s not straightforward, but it doesn’t require a third party app.

2. neither windows nor Mac have this audio routing feature built in without a third party app or an app that installs with the drivers. (To my knowledge)

3). Command + ` (~, or backtick) will switch between windows of the same app. Using shift will reverse it.

I’d strongly suggest using a trackpad with macOS, as the multitouch gestures are very useful for desktop navigation, especially when there are a lot of apps open. macOS also has “Spaces” which is similar to Virtual Desktops in windows. Spaces can also be “split views” where two apps are set to be full screen (maximized, without a menu bar) on the same window with the ability to size them. This is particularly useful for me when working on iOS apps or websites.