Volume shortcut!

45-day free evaluation period.

In this case I choose to pair Volume Up with Control-Option-Command-Up_Arrow, only because at the moment I'm using my Touch Bar 15" Macbook Pro, and tapping the volume up key is annoying. On a keyboard with a volume up key, I would just press the volume up key for the "Key Sequence" field, and BetterTouchTool would associate the mapping with whatever key code the keyboard send for your volume up key.

I then associated the key sequence with Volume Up (see below for for pop-up menu I selected Volume Up from

Here I choose Control-Option-Command-Down_Arrow (same reason because I'm using a touch bar Macbook Pro). I associated this key sequence with Volume Down

This is a selection menu. There are a few hundred standard functions you can choose from. I'm just showing the beginning of the standard keyboard keys that include the media controls.

You can assign the function to specific App or as a global.

And some of those keyboards come with their own device drivers to provide those services.

BetterTouchTool is not very expensive, and will give you a gazillion keyboard, mouse, trackpad, window snapping.

$7.50 U.S. for 2 years of updates, $21 for lifetime.

https://bettertouchtool.net

I often use BTT to create hotkeys that are consistent across multiple apps, such as the same hotkey that will move left or right through the window tabs for different apps that all seem to have different hotkeys, but with BTT I can give all of those apps the same hotkey (and I also give them all the same trackpad gesture; I use the Bluetooth Magic Trackpad II with my desktop Mac at work).

I have been using BetterTouchTool since 2010 and it has never given me any trouble, and has just gotten better and better over the years. I can not always say that about some of the 3rd party keyboard drivers for their 3rd party keyboard.

Probably because you can't.

Try BetterTouchTool or Keyboard Maestro

Do you mean non-Mac or non-Apple? There are any number of non-Apple keyboards with built-in media keys.

All I can tell you is some apps have keyboard shortcuts already. Such as Apple Music which uses Command + Up/Down arrow keys.