WinRAR 7.12

How can I create a keyboard shortcut for compressing files in Windows? Is it possible?

Well, you could use the command line proggie in the WinRAR directory "rar.exe". Create a batch file put it in the Sent-To folder. Right click on the directory you want to compress and choose your batch file from the Sent-To menu.
You could also use the program FileMenu Tools and create a additional context menu entry to right click on the directory you want to compress and choose that entry from your context menu.
Keyboard shortcuts you can define with HotKey Plus:
https://www.brianapps.net/hotkeyplus

To @jekyll and anyone who wants to both create and extract rar files on MacOS:
https://www.rarlab.com/download.htm
has commandline versions to download. Mac versions are available for Intel and Apple silicon. You can build wrapper scripts for easier compression and decompression.
Not as convenient as a GUI app but no rocket science either.
And I like how rar can create archives with a redundant recovery record that can be used to repair broken archives (within limits of course).

Honestly, we shoud support WinRAR. We almost use it for anything, even more than a torrent downloader.

Once R2R said: "Support Good Developers"

Do you need WinRAR to open this?

If this was much cheaper, I'd buy it. Like £5. I'd buy it. But they are charging too much. No idea about price points and what the market will pay.