Hello,
How do I create a keyboard shortcut for "Save as PDF", see screen-shot 
Thanks!
Try a keyboard shortcut that → triggers menu bar item → Save as PDF
Not on my computer rn to check the exact terms 
For Preview you'd use "File;Export as PDF..."
Although that is a bit different than using the one from the print dialog. Is there a reason you need that one?
Not the same thing... if you have multiple pages Export does not control if you want to save just some of the pages...
In the MacOs keyboard Shortcuts settings, the shortcut works, if you create one for "All Applications" with Save as PDF, it works... but I want to have it in BTT.
Unfortunately macOS doesn't make it easy to trigger items from such custom drop-down menus. However setting a shortcut in System Preferences (maybe some obscure one you don't need anywhere else) and then calling that shortcut using BTT's send Keyboard Shortcut feature would probably work:
Otherwise I think the only good solution would be to build some little Apple Script / Automator workflow that clicks the button - but that's probably overkill.
Got it, thanks for the explanation.
I will try that