shortcus

Is there a possibility in macOS Catalina 10.15 to set a keyboard shortcut for a particular key, for example the "r" key?

I want to create a shortcut that disables all notifications when I open an app (including banners (so dnd is not what I want)), and when I close that app the shortcut enables back all notifications. To do that I need to change the value of "show previews" in the settings. How can I do it?

I was doodling it but have not found anything usable. I am quite confused from word shortcuts used in both situations. Can I use Siri shortcuts in Apps use somehow as classical shortcuts within iOS? I can make shortcut working with Siri but I have not found way to do opposite. Example...