Yes, there is a function selection that will allow you to activate Siri on your mac using a button on your Quick Keys.

To start, you must open the Settings panel and decide which button on your Quick Keys you want to use to activate Siri.

Note: The Siri activation feature can be added to any Quick Keys, Tablet, or Pens button.

With the Setting panel open.

[1] Select My Quick Keys.

[2] I have chosen to have this feature assigned to "all others."

[3] And I'm going to have it assigned to button #4.

[4] Select Application from the Menu > [5] Siri

And click OK to save it.

[6] Siri is now added to Button 6 on your Quick Keys.

Siri is now displayed on the Quick Keys OLED Display for easy selection and activation.